INTRODUZIONE
S COPO DEL DOCUMENTO
This document presents the findings of an investigation into reference technologies related to the technical and organizational challenges associated with the "Virtual Shopping Center Prototype" initiative It also provides a summary of the market offerings concerning products, environments, and specific IT and telematics solutions relevant to this line of work.
Given the nature and type of technologies examined, as well as their corresponding market products, the findings presented in this document can serve as a reference for other research lines within the Cluster In such cases, and only for common technologies, the technical annex of the other research lines will explicitly reference the technological investigations described herein, thereby providing a comprehensive overview of the examined technological aspects and the related design choices made.
D EFINIZIONI , ACRONIMI E ABBREVIAZIONI
Qui vanno inserite, se presenti, le definizioni e gli acronimi utili per la lettura e la comprensione del documento.
D OCUMENTI DI RIFERIMENTO
Qui vanno inserite, se presenti, i riferimenti a documentazione esterna (manuali, siti Web dei produttori, etc ) e/o bibliografia utilizzata nel corso dell’indagine tecnologica.
C ONTENUTI
il Capitolo 1 descrive lo scopo del documento e il suo ambito applicativo
Each subsequent chapter provides a detailed description of the analyzed technological areas and their corresponding reference standards, along with a thorough examination of the market products reviewed during the study, highlighting their functional features and supported technologies.
Nelle Appendici, infine, troveranno posto i riferimenti normativi e bibliografici a supporto dell’indagine tecnologica svolta.
SCENARIO TECNOLOGICO: PAGAMENTO ELETTRONICO
D ESCRIZIONE DELL ’ AREA TECNOLOGICA
E-commerce holds a vital position among the new services available on the Internet It enables businesses and commercial operators to showcase their products and services online to a potential market of millions of users This allows consumers to easily purchase and pay for goods and services from suppliers using a simple personal computer.
The growth of e-commerce was previously hindered by the need for secure payment mechanisms suitable for various types of purchases, as well as the lack of standardized methods for safely transferring financial information online.
In the past, individuals wishing to make online purchases had to ensure payment through traditional methods, such as providing their credit card number via fax, phone, or regular mail.
Currently, very few users in Europe are willing to share their financial data, such as credit card numbers and bank details, online As a result, many virtual stores use the internet merely as a showcase, resorting to parallel payment methods that rely on traditional channels The costs and time associated with these alternative payment mechanisms often negate the actual convenience of using the internet for buying and selling goods and services.
It is clear that the implementation of new security measures and reference standards for online payment mechanisms is essential for the success of e-commerce.
Today, the security issues surrounding electronic payment systems have largely been addressed Numerous solutions worldwide provide secure electronic payment services through shared systems among commercial organizations and financial networks, utilizing proprietary security protocols.
Major international credit card networks and leading technology providers have established universally accepted protocols for secure online payments using credit cards (SET) They will release application software implementing these protocols within the next few months.
These premises provide a solid foundation for rapid growth in e-commerce starting next year This growth will be most pronounced in the United States, where socio-cultural conditions favor the adoption of this new business channel However, Europe and Italy are also expected to experience swift investment and expansion in this sector.
Qualunque forma di commercio, compreso quello elettronico, coinvolge sempre un compratore e un venditore, che effettuano delle transazioni economiche in cui scambiano denaro e beni e/o servizi
In e-commerce, the involvement of a third party, specifically a financial institution, is essential for managing payment transactions Many existing payment systems divide this role into two components: the Issuing Institution, which interacts with the buyer, and the Receiving Institution, which engages with the seller.
The issuing institution establishes a bank account and/or credit card for the buyer, ensuring the seller receives payment for transactions conducted in compliance with local laws and credit card agreement terms Simultaneously, the receiving institution opens a bank account for the seller, where the funds from the buyer are deposited following a purchase transaction.
In un sistema di pagamento elettronico è possibile suddividere il flusso di denaro come segue:
Da Istituto di Emissione a Compratore (Prelievo);
Da Venditore ad Istituto Ricevente (Deposito);
Da Istituto di Emissione ad Istituto Ricevente (Compensazione).
The financial compensation phase enables the settlement of mutual debts and credits among the involved financial institutions, effectively facilitating transactions between buyers and sellers Consequently, electronic payments result in an actual transfer of funds from the buyer to the seller through the issuing institution and the receiving institution.
I sistemi di pagamento elettronico vengono suddivisi in due tipologie di modelli:
Sistemi “Cash-like” o Pre-Paid
Sistemi “Cheque-like” (Pay-Now e Pay-Later)
An electronic payment system is referred to as "Cash-like" or Pre-Paid when a specific amount is charged to the buyer's bank account before any purchases are made, allowing that sum to be used for future payments.
Payment systems such as electronic wallets, electronic cash registers, and those based on the concept of electronic currency fall into this category Notable examples include the E-Cash system from Digicash and CyberCoin from CyberCash, which are discussed in detail below.
La seguente figura illustra i tipici flussi di denaro in un sistema di pagamento di tipo
Figura 1.1.1: Transazioni nei Sistemi di Pagamento “Cash-like”
In electronic payment systems categorized as "Cheque-like," payments are made by sending a certificate or document from the buyer to the seller, such as a check or credit card receipt, which serves as proof of the payment order These payment systems can further be functionally divided into various types.
Pay-Now systems are defined by the immediate debit from the buyer's bank account at the time of payment This category includes systems that utilize ATM cards (debit cards).
T ECNOLOGIE DI R IFERIMENTO
The primary challenge of electronic payment systems lies in the authorization process, which ensures that honest buyers can successfully complete transactions with sellers while preventing dishonest individuals from making unauthorized purchases This includes safeguarding against scenarios such as double spending of the same funds or sending duplicate messages to multiple sellers.
Tutto ciò, inoltre, deve essere realizzato senza danneggiare in alcun modo la privacy dei compratori e venditori onesti.
Verranno di seguito analizzate le tecniche principalmente utilizzate per raggiungere il suddetto obiettivo e per rispondere ai requisiti di sicurezza descritti nel precedente paragrafo.
2.2.1.1 Sistemi on-line ed off-line
Per eseguire operazioni di pagamento utilizzando mezzi elettronici ed in particolare reti telematiche, si possono realizzare due tipologie di sistemi:
Sistemi on-line, che eseguono le transazioni economiche interamente sulla rete;
Sistemi off-line, che eseguono le transazioni economiche ricorrendo,parzialmente o completamente, al supporto di mezzi trasmissivi tradizionali quali telefono o fax.
Online systems require an authentication and authorization server, typically located at the buyer's or seller's bank, for every payment transaction In contrast, offline systems do not necessitate such a server, as authentication and authorization occur offline and not during the transaction execution.
In offline payment systems, ensuring the financial reliability of the buyer necessitates the installation of specific hardware These systems particularly require "anti-intrusion" hardware, such as smartcards, on the buyer's side, and may also involve the presence of Point of Sale (POS) terminals at the seller's location.
The use of these tools for online purchases would require the adoption of additional devices, leading to increased costs and management challenges Furthermore, the need for a smart card reader installed on the buyer's personal computer or workstation presents a significant technical barrier.
Online systems undoubtedly necessitate increased information exchange between the parties involved in economic transactions; however, they do not inherently require specific anti-intrusion hardware at either the buyer's or seller's end.
La maggior parte dei sistemi di pagamento su Internet è di tipo on-line.
Cryptography is a mechanism that processes information using "keys" to make it unreadable to unauthorized users Only individuals who possess the correct key can decrypt and access the content of the messages.
I metodi di crittografia largamente utilizzati sono due:
Crittografia Simmetrica o a chiave segreta condivisa;
Prima di analizzare in dettaglio i due differenti metodi di crittografia ed i relativi algoritmi esistenti, è necessario evidenziare che esistono dei sistemi di pagamento elettronico senza crittografia.
Not using encryption relies on "out-of-band" security methods For instance, electronic goods or services ordered by a buyer will not be delivered until the buyer has sent a fax, letter, or made a phone call to confirm the order.
Esempi di questo tipo di sistemi sono CompuServe , First Virtual ed Internet
In CompuServe's Shopping Network, buyers communicate through a secure line and have an account that requires a password in exchange for their credit card number However, this password is not protected during transmission over the internet, making it vulnerable to interception and tampering While First Virtual offers some protection by requiring email confirmation for each payment, true security lies in the buyer's ability to cancel the purchase within a specified timeframe, placing the full risk on the seller until that point.
La crittografia simmetrica, o a chiave segreta condivisa, utilizza un’unica chiave sia per criptare sia per decriptare i messaggi.
Entities exchanging encrypted information must share keys bilaterally, which is inefficient in the vast environment of the Internet, where numerous unknown correspondents exist Consequently, a merchant aiming to conduct secure transactions with hundreds of buyers would require a unique secret key for each individual, complicating the process significantly.
Il primo algoritmo di crittografia simmetrica è stato il DES (Data Encryption
Standard) sviluppato da IBM, NSA (National Security Agency) e da NBS (National Bureau of Standard) ora NIST ed adottato dal governo degli Stati Uniti come standard ufficiale.
DES defines a set of encryption algorithms that operate with 64-bit blocks and 56-bit keys While it is highly efficient in block data encryption, recent research has indicated the potential for attacks on the code using a new technique known as differential cryptanalysis.
Tuttavia la rottura del codice con questo tipo di tecnica non è molto pratica in circostanze normali, in quanto richiede un’enorme quantità di potenza computazionale.
Kerberos is a widely recognized authentication system that utilizes the DES algorithm and was developed at MIT It features a dedicated network site known as the Kerberos Server, which centrally manages the keys used and performs essential cryptographic functions for all information exchanged between different entities.
Asymmetric cryptography, also known as public key cryptography, employs a pair of keys: one for encrypting messages and the other for decrypting them These keys are designed so that a message encrypted with one key can only be decrypted with the other, and vice versa This unique characteristic of using two different keys is what gives this technique its name.
Ciascuna entità, coinvolta in una transazione sicura basata su tale tipo di crittografia, possiede due chiavi:
Chiave Pubblica, da distribuire a tutte le entità con cui si vuole comunicare;
Chiave Privata, da non divulgare.
Anyone with access to the public key can encrypt messages, which can only be decrypted using the corresponding private key Conversely, if data is encrypted with the private key, it can be decrypted using the public key.
Using this technique, an entity that needs to exchange secure messages with multiple parties must share its public key with all other entities and can decrypt messages using its private key For instance, a merchant wishing to conduct secure transactions with hundreds of buyers requires only one private key.
There are numerous asymmetric encryption algorithms, but RSA, named after its creators Rivest, Shamir, and Adleman, is the most widely used due to its simplicity and compatibility with other systems The RSA algorithm relies on the principle of factorization and is highly secure against potential attacks.
RSA viene utilizzato nella maggior parte dei sistemi pagamento elettronico, sia per la crittografia dei messaggi, sia per l’autenticazione.
S TANDARD DI R IFERIMENTO
Currently, there are no established standards for electronic payments on the Internet However, efforts by various standardization organizations, alongside major technology providers and financial institutions, are focused on developing these essential standards.
The European Committee for Standardization (CEN), along with financial companies such as Europay, MasterCard, and VISA, is collaborating to establish a standard for a credit card-based payment system.
Various systems, such as FirstVirtual, CyberCash, and IBM's iKP, have been brought to the attention of the Internet Engineering Task Force (IETF), which established a working group in December 1995 to develop a standardized approach.
In the United States, both MasterCard and Visa aimed to establish an industrial standard for secure e-commerce payment systems Initially collaborating, MasterCard later partnered with IBM and Netscape to develop its own protocol, known as SEPP, while Visa joined forces with Microsoft to create STT (Secure Transaction Technology).
From a technical perspective, SEPP and STT protocols are fundamentally similar, as they both utilize the same payment model, protocol type, and encryption mechanisms SEPP is essentially a variant of iKP, while STT, designed independently, is semantically equivalent to 3KP The key differences lie in specific technical details: SEPP, like iKP, encrypts only relevant data such as payment and buyer authentication details, whereas STT encrypts all data Additionally, SEPP adheres to standard procedures like X.509, while STT largely avoids standard adoption The primary distinction, however, is in their foundational policies: STT is designed for a proprietary network, whereas SEPP is based on proposals discussed in open working groups like iKP.
In November 1995, MasterCard presented SEPP to the American National Standards Institute (ANSI) to initiate discussions on developing a standard However, ANSI's status limited the discussion to U.S.-based organizations only Consequently, it was decided to submit SEPP for examination by the International Organization for Standardization (ISO).
In early 1996, Visa and MasterCard, with the technical guidance of a consortium of tech companies including Microsoft, Sun, Netscape, IBM, Terisa System, and VeriSign, established common specifications for an electronic payment system utilizing credit cards.
SET (Secure Electronic Transaction), che potrebbe divenire rapidamente uno standard “de facto” per la gestione dei pagamenti sicuri su Internet tramite carte di credito.
Simultaneously, the World Wide Web Consortium (W3C) launched the Joint Electronic Payment Initiative (Jepi) aimed at establishing a framework for interoperability among various payment methods by implementing the Payment Extension Protocol (Pep) Pep is an HTTP extension designed to identify different payment types and is currently under review by the Internet Engineering Task Force.
The primary goal of Jepi is the Universal Payment Preamble, which aims to establish a standard for negotiating various payment methods, including SET and smart cards The W3C seeks to enable all forms of online payment, while major credit card companies focus on ensuring that credit cards remain the predominant method for online transactions Meanwhile, providers, believing they have found the necessary technology for online business in SET, are not waiting for the W3C's decisions Consequently, the W3C is currently assessing whether to continue its work on Jepi.
The OBI (Open Buying on the Internet) protocol, promoted by American Express and Supplyworks, aims to establish a foundational framework for business-to-business e-commerce on the Internet This initiative seeks to facilitate commercial transactions in a manner similar to how SET has enhanced the credibility of credit card usage for online purchases The OBI standard outlines the reference architecture, technical specifications, and a set of guidelines for developing B2B e-commerce applications, focusing on managing the workflow associated with business transactions between organizations, such as procurement and sales processes.
The OBI standard facilitates various payment methods for transactions, allowing for the integration of emerging options in the market, while intentionally avoiding the standardization of the payment process itself.
Currently, it can be concluded that the only standardization activity related to online payment mechanisms likely to achieve international recognition is SET Below is a brief description of the technical and functional characteristics of this protocol.
Il SET è un protocollo per la realizzazione di transazioni di pagamento sicuro su Internet tramite carta di credito.
The SET specifications were collaboratively developed by Visa and Mastercard, alongside their technology partners Microsoft and Netscape Numerous financial organizations, such as American Express, and technology firms like SUN, IBM, and RSA Data Security, have shown support for the SET specifications and contributed to their development.
Molte delle società informatiche che hanno partecipato alla messa a punto di tali specifiche, hanno annunciato per il 1997 l'uscita commerciale di pacchetti software in grado di implementare il SET.
Il protocollo SET potrebbe avere uno sviluppo particolare in Europa, dove è in corso un progetto pilota di commercio elettronico, promosso da VISA, iniziato ai primi del
In 1997, a project was initiated that would come into effect at the beginning of 1998, involving around forty European financial institutions associated with VISA across 16 countries Among these, eight are based in Italy, including Servizi Interbancari (Cartasi), Deutsche Bank Italia (Bankamericard), Bnl, Cariplo, Banca Sella, Banca Antoniana Popolare Veneta, SSB (Società Servizi Bancari), and Setefi These institutions collectively account for over 90% of VISA card usage in Italy.
In the SET specifications, alongside traditional parties in a commercial transaction—the buyer, seller, and financial institutions (Buyer’s Bank, credit card provider, and Seller’s Bank)—there is a crucial entity known as the Payment Gateway This device operates at the seller's bank and is responsible for processing financial messages and requests from all parties involved in the transaction, issuing the necessary authorizations Essentially, it serves as the interface between the current financial network and the Internet.
Tutte le entità coinvolte in una transazione SET devono essere in possesso di un certificato utilizzato nel corso della transazione per il raggiungimento dei requisiti di sicurezza.
P RODOTTI DI MERCATO
This paragraph provides concise descriptions of various electronic payment systems available for international use in facilitating e-commerce services.
This list is not intended to be exhaustive, as there are numerous operators, particularly in the financial sector, offering similar mechanisms Instead, it aims to highlight the most significant examples based on the technology employed and their potential for widespread adoption.
2.4.1 Sistemi di pagamento basati sull’utilizzo di Monete Elettroniche
Caratteristiche funzionali, prestazionali ed operative
Ecash è stato il primo sistema di pagamento elettronico su Internet basato sull’utilizzo di monete elettroniche, sviluppato da DigiCash.
Ecash is a client-server software that enables secure financial transactions from any computer with the Ecash client installed, allowing buyers to conduct transactions over the Internet safely.
Le entità coinvolte in una transazione ecash sono le seguenti:
Banche, che emettono la moneta elettronica, convalidano quella esistente sui conti dei clienti e la scambiano con quella reale;
Compratori, che devono avere un conto presso una delle banche aderenti al sistema ecash, da cui prelevare o depositare moneta elettronica, tramite la componente client di ecash;
Venditori, che devono accettare moneta elettronica ecash in cambio di beni/servizi venduti Anche i venditori devono avere un conto presso una delle banche convenzionate ecash.
The eCash client enables users to send and receive payments seamlessly with any other user on the Internet who utilizes the same client Both buyers and sellers are not required to use any specific hardware, while the bank is equipped with encoding hardware that ensures the speed and reliability of transactions, alongside an eCash server component.
Using the Ecash client, buyers can withdraw electronic banknotes from participating banks This withdrawal process occurs through an online transaction directed to the specific Ecash server of the bank.
Il prelievo avviene nel seguente modo:
il compratore invia alla banca una richiesta di un certo numero di monete elettroniche;
a ciascuna banconota viene associato un numero pseudocasuale generato dal client ecash che risiede sul computer del compratore e garantito univoco (numero di serie);
The buyer submits the serial numbers of the banknotes to the bank for validation through a "masking" mechanism, allowing the bank to verify the currency without accessing the actual serial numbers, ensuring confidentiality through a blind signature process.
la banca individua il cliente che sta effettuando il prelievo, addebita il corrispondente importo sul conto bancario, convalida le monete elettroniche e le invia, firmate digitalmente, al cliente.
When electronic banknotes are withdrawn, they are stored on the buyer's computer hard drive and managed through ecash client software Access to these electronic banknotes is secured by a password known only to the buyer, ensuring that even the bank does not have access to this information.
Le monete elettroniche presenti sul computer del compratore, possono, a questo punto essere spese presso qualunque negozio virtuale convenzionato.
Quando il compratore vuole acquistare dei prodotti utilizzando ecash, vengono eseguiti i seguenti step:
After selecting products from a sales server and preparing the purchase order, the buyer sends the corresponding amount of electronic money, or ecash, to the seller without employing serial number masking.
il software ecash del venditore invia le monete elettroniche ecash (numeri di serie) alla banca per la verifica;
la Banca controlla la validità delle monete verificando che i numeri di serie delle stesse non siano presenti nel database delle monete “già spese”;
When the bank verifies the validity of the banknotes, it credits the corresponding amount to the seller's account, records the serial numbers of the spent notes in its database, and sends a notification to the seller.
Il sistema ecash garantisce la riservatezza e l’integrità dei dati utilizzando tecniche di firme digitali e crittografia a chiave pubblica.
One of the key advantages of this system is the ability to preserve buyer anonymity There is no way for either the company receiving the electronic currency or the bank to trace the identity of the purchaser As a result, it is impossible to track what is being bought, who is buying it, where, and when.
The ecash mechanism can be utilized for small transactions, known as micropayments, although it may not be the most efficient option for computational processing This makes it a viable alternative to credit card-based payment systems, which struggle to handle such low-value transactions effectively.
La somiglianza con meccanismi di pagamento tradizionali tramite denaro contante è evidente Questo rappresenta un vantaggio dal punto di vista della facilità d’uso e della accettazione da parte degli utenti.
Dei problemi ancora aperti da un punto di vista tecnico, sono una gestione efficace di eventuali resti e la gestione dei cambi tra banconote elettroniche emesse in differenti valute.
“Blind Signatures” – soluzione proprietaria DigiCash
Currently, the ecash electronic payment system relies solely on software However, future plans include the release of an electronic card and a corresponding reader, which will enhance user security and allow for greater portability of ecash across different computers.
DigiCash prevede il coinvolgimento di molti altri istituti finanziari nel corso del
1997, presupposto indispensabile per la diffusione di tale sistema di pagamento.
Per poter utilizzare il sistema ecash è necessario che sia i compratori che i venditori abbiano un conto presso una delle Banche convenzionate Ecash.
Dal 23 Ottobre 1995, Mark Twain Bank (USA) supporta i pagamenti tramite Ecash in dollari americani Dal 13 Marzo 1996, Eunet Finland in cooperazione con Merita Bank supporta i pagamenti tramite Ecash in valuta Finlandese Il 7 Maggio 1996 è stata annunciata una cooperazione tra Ecash e la Deutsche Bank, ma al momento tale banca non supporta pagamenti reali con moneta Ecash.
DigiCash does not sell its Ecash software directly but instead licenses it to banks To use Ecash on a web sales server, users must partner with one of the affiliated banks The cost of utilizing the Ecash software varies based on the agreement made with the chosen bank.
Ecash client: software da installare sul PC del compratore Disponibile per ambiente
Windows, Macintosh ed X-Windows Funziona con qualsiasi browser disponibile sul mercato.
The Ecash server is a software solution designed for installation on sales servers, which integrates seamlessly with sales applications This server software is compatible with Windows 3.1 and later versions, including Windows 95 and Windows NT, as well as Unix platforms.
SCENARIO TECNOLOGICO: SISTEMI DBMS
D ESCRIZIONE DELL ’ AREA T ECNOLOGICA
The Relational Model has been the established standard for data models since the 1980s, becoming an integral part of our understanding of information organization Relational Database Management Systems (RDBMS), which utilize this data model, are considered a mature technology This technological investigation emphasizes the evolving trends of RDBMS rather than merely describing the current technology, alongside a comparison of available market products.
In many companies, there is a noticeable increase not only in the volume of information but also in its diversity Information is undoubtedly one of the most valuable internal resources for businesses, as it supports strategic decision-making and enhances production and management processes.
A more effective use of information is essential for improving overall business performance To achieve this, specialized systems are introduced for data collection, transformation into actionable information, and analysis This leads to the concept of a Data Warehouse, defined as a centralized repository of information related to a specific area of interest Data is gathered and extracted from operational systems, organized according to clear criteria to support the decision-making process.
A Data Warehouse can be envisioned as a structured and efficient repository where business-critical information is stored in an organized manner, making it easily identifiable and accessible By facilitating the decision-making process, a Data Warehouse falls under the broader category of Decision Support Systems (DSS).
A Data Warehouse consists of three essential components: software for designing and extracting, transforming, and loading data from various sources, often external to the organization; a database management system (DBMS) where the data is stored; and a set of tools for accessing and analyzing information available to end users The DBMS thus assumes a new role within the organization, becoming a crucial component of the Data Warehouse.
The DBMS, when utilized as a tool for Data Warehousing, must enhance its capabilities to effectively manage complex data and metadata, which includes information about the stored data and the rules for utilizing that information.
The alphanumeric data format is no longer adequate for representing complex data, leading to the evolution of relational database management systems (DBMS) to incorporate a new data type: BLOB (Binary Large Object) BLOBs enable the storage of complex data as sequences of bits without any internal structure However, they do not allow for manipulation of the data itself, except for queries related to any associated attributes.
In recent years, two schools of thought have emerged regarding the evolution of Database Management Systems (DBMS) On one side, experts like Atkinson and Stonebraker advocate for the transition from relational systems to object-oriented DBMS to effectively manage complex data that cannot be represented by traditional alphanumeric formats Conversely, figures such as Codd, Date, and Darwen argue for the irreplaceability of the relational model.
The evolution of database management systems (DBMS) has led to a more comprehensive integration between object-oriented and relational databases, resulting in the emergence of Object-Relational DBMS This innovative system enables the management of complex data while retaining the ease of querying through SQL and adapting to network architectures typical of relational systems.
In object-oriented technologies, any type of object can be categorized into a class, and each class can possess specific methods to manage the information contained within it.
In a database, various objects such as images, sounds, texts, and even web pages can be included, facilitating interaction between DBMS and the Internet Unlike traditional relational DBMS that associate objects with alphanumeric records, this approach allows for the manipulation of the contained information In an Object-Relational Database Management System (O-RDBMS), data types are not standardized from the outset, giving users the theoretical ability to create their own data types and query functions.
The main current models of Database Management Systems (DBMS) — relational, object-oriented, and object-relational — are in competition with one another, as each is better suited to meet the specific requirements of different application classes.
Query DBMS relazionali DBMS relazionale ad oggetti
Il vantaggio dei DBMS relazionale ad oggetti consiste proprio nel riuscire ad integrare in un’unica architettura soluzioni sorte da esigenze contrastanti.
Molti produttori si stanno orientando in questa nuova direzione, rilasciando dei nuovi prodotti spesso chiamati “Universal Server” o
Universal Databases enable the management of complex data, exemplified by Oracle Corp.'s Oracle Universal Server 8, Informix Software Inc.'s Informix Universal Server, and IBM Corp.'s DB2 Common Server Microsoft Corp offers OLE DB, a "universal" access mechanism for both tabular and non-tabular data sources through specific drivers In contrast, Computer Associates International Inc advocates for a "pure" object DBMS separate from relational DBMS, while Sybase Inc supports an integration layer above the relational DBMS and specialized servers for different types of information.
T ECNOLOGIE DI RIFERIMENTO
Like other IT product categories, database management systems (DBMS) evolve at such a rapid pace that it becomes nearly impossible to assess which products offer more or fewer features In fact, the products discussed typically share similar characteristics, often differing only in minor details, and many of the required functionalities are already available in the new beta versions.
To enhance the evaluation of various products, the following descriptive notes outline the technical specifications that effectively differentiate and comment on the offered features These notes are organized by categories of functionality.
While all analyzed products adhere to the fundamental principles of the relational data model, such as storing data in tables and accessing it through high-level operators primarily in SQL, the evaluation of more advanced relational model features reveals differences All products claim to support declarative integrity constraints, except for domain constraints However, a closer inspection shows that they primarily support the declaration of key columns and referential integrity constraints Only Informix and Oracle provide support for cascading deletes as a violation of referential integrity constraints, and only DB2 fully complies with the ANSI SQL-92 standard, including options for set null, cascade, and no action.
Attention should also be given to how constraints are implemented For instance, most examined products utilize hidden indexes to enforce primary keys and unique constraints Furthermore, DB2, Informix, and Oracle do not allow the creation of unique indexes on a column that has already been indexed with a unique constraint.
All the products mentioned support BLOBs (binary large objects), which can be used to store images, documents, sounds, and other types of unstructured data However, it's important to note that BLOBs are processed by the front-end languages and tools used to develop applications, and not all of these languages and tools handle such complex data types effectively.
Another crucial factor to consider is how triggers are implemented Some products utilize their own trigger mechanisms to enforce declarative integrity constraints, which is essential for establishing management rules through triggers.
CA-OpenIngres features row-based triggers, known as rules, that activate following triggering operations This allows for multiple triggers per table, each with a unique name, enabling modular implementation of management rules.
DB2, Informix, and Oracle offer both set-based and row-based triggers that can be activated before or after specific operations However, these systems allow only one trigger per condition, which may require the integration of unrelated management rules into a single trigger Despite this limitation, it is possible to call different stored procedures for each processing function.
The locking levels offered by various DBMS have been a widely debated topic among producers It's not entirely accurate to claim that row-level locking is superior to page-level locking, as the effectiveness of each depends on the application's isolation and performance requirements, taking into account its concurrency control needs.
All evaluated products claim to support the Entry Level ANSI SQL-92 standard, which is limited to basic database manipulation and definition operations, unlike the Intermediate and Full levels.
All examined DBMS support the outer join operation; however, only CA-OpenIngres employs the correct ANSI SQL-92 syntax, explicitly specifying the outer join in the FROM clause of the SELECT statement In contrast, other products utilize an asterisk or a plus sign in the join conditions within the WHERE clause.
Support for distributed databases varies significantly among different products Only Oracle includes this support as part of its core offering In contrast, CA-OpenIngres, DB2, and Sybase provide a multi-database shell that allows access to remote tables When performing transactions on these remote tables, these three products implement the two-phase commit (2PC) protocol Other database products only allow the implementation of the 2PC protocol programmatically within the application.
Oracle, Sybase, and SQL Server provide remote procedure calls (RPC) that enable access to remote database data as if it were local For instance, a stored procedure invoked by an application can perform integrity checks on a remote database without the application needing to manage this process Notably, Sybase offers a particularly robust implementation of RPC.
Replication is a unique aspect of DBMS that warrants separate analysis due to various factors such as types, architectures, functionalities, management, monitoring tools, and performance For truly replicated databases, it is crucial to have the capability to replicate transactions with a bidirectional peer-to-peer configuration.
Dei DBMS selezionati solo DB2, CA-OpenIngres, Oracle, and Sybase possono essere configurati per replicare le transazioni in peer-to-peer bidirezionale.
Another important aspect to consider is the replication towards heterogeneous DBMS, which most products address with their gateway solutions However, only a few, such as Sybase Replication Server through its Enterprise Connect middleware, can effectively replicate data to and from various sources.
P RODOTTI DI MERCATO
This technological investigation focused on DBMS operating on Unix and Windows NT platforms The selection was made based on market share, as these widely used systems enable manufacturers to provide strong pre- and post-sales support, along with ongoing product evolution Consequently, the analysis was narrowed down to six key products.
Each product features a concise description along with a technical sheet detailing its specific functionalities, which are organized into categories At the end of the sheets, common notes are provided for all products, allowing for a comparison based on functionality classes.
Oracle Universal Server, which includes Oracle7 (v 7.3), aims to integrate the capabilities of the leading relational DBMS with web functionality, text management, messaging, and multimedia information This multimedia information seamlessly combines relational, spatial, text, audio, and video data, making it accessible to any user with a web browser who connects to a web-enabled database.
The Oracle Universal Server architecture aims to provide users with an integrated platform designed to meet various needs, including support for Network Computer Architecture (NCA), Online Transaction Processing (OLTP), Online Analytical Processing (OLAP), and Data Warehouse applications.
Limitate, ad eccezione del cascading delete
Referential nella clausola WHERE No
Tipi dati definiti dall’utente Si
Tipi dati Image, video, text, messaging, spatial aggiuntivi
Struttura delle tabelle Heap, clustered
Struttura degli indici B-tree, bitmap, hash
Tuning Allocazione tavole ed indici
Livello Row-based, set-based
Livello di Lock Tabella, riga
Tool Oracle Enterprise Manager, Performance Pack Supporto SNMP Si
Qualunque sorgente dati MVVS attraverso EDA/SQL (Adabas, IDMS, IMS, SQL/DS, VSAM), qualunque sorgente dati, AS/400, DRDA, DB2, TurboImage, Sybase, Rdb, RMS, Informix, CA-Ingres, SQL Server, Teradata
Distribuiti Parte del prodotto base
Verso altri DBMS Attraverso gateway
Sistemi Operativi La maggior parte dei sistemi Unix, Windows NT,
VAX VMS, Windows 95, OS/2, Macintosh
Sybase has long been recognized as one of the most technologically advanced relational DBMS However, the launch of Sybase SQL Server 10 faced criticism due to its low product quality In response, Sybase SQL Server 11 was developed following the ISO9000 certification process to enhance product quality and meet performance demands from customers and analysts, while also addressing competitive pressures The result is a redesigned, scalable, and configurable DBMS optimized to maximize the performance of underlying hardware and operating systems.
Update sulle viste (con opzione check)
Tipi dati definiti dall’utente Si
Tipi dati aggiuntivi Binary, image, money, bit, text, varbinary
Struttura delle tabelle Heap, clustered
Pre-fetch indici, I/O buffer cache, formato blocchi, partiziona-mento tavole
Livello di Lock Tabella, pagina
ANSI SQL Entry-Level SQL-92
Tool Sybase SQL Manager, SQL Monitor
Adabas, A S/400, DB2, IDMS, IMS, Informix, Ingres, ISAM, Microsoft SQL Server, Oracle, Rdb, RMS, file sequenziali, SQL/DS, Sybase
Formato Tabelle Dipendente dalla memoria
La maggior parte dei sistemi Unix, Windows NT,VAX VMS, Windows 95, OS/2, Macintosh
Informix offre una vasta gamma di DBMS server, da Informix-SE, per applicazioni medio-piccole ad Informix OnLine Extended Parallel Server per sistemi Massively Parallel Processing (MPP).
Informix-OnLine Dynamic Server 7.2 for Unix is a multi-threaded database server built on the Informix Dynamic Scalable Architecture (DSA) It utilizes a dynamic set of database server processes, known as virtual processors, along with multiple concurrent threads to handle client requests in parallel Each virtual processor is assigned to a specific task class, allowing the database server to schedule threads and manage their priority independently of the operating system.
This DBMS features dynamic allocation and deallocation of shared memory, enabling efficient resource management The server can dynamically balance the load based on available resources, while asynchronous I/O is facilitated through dedicated threads These threads can pre-fetch data during sequential scans or index searches Additionally, indexes and data can be constructed and loaded in parallel, and the Parallel Data Query (PDQ) option implements vertical parallelism in queries.
Limitate, ad eccezione del cascading delete
Update sulle viste (con opzione check)
Tipi dati definiti dall’utente
Tipi dati aggiuntivi Byte, testi sino a 2GB
Struttura delle tabelle Nessuna scelta
Struttura degli indici B+ tree, clustered
Informazioni per il Tuning Extents, Frammentazio-ne tavole
Livello Row-based, set-based
Timing Before, for each, after
Livello di Lock Database, tabella, pagina, riga
ANSI SQL Entry-Level SQL-92
API ESQL, TP/XA, CLI, ODBC
Tool SMI, DB/Cockpit, OnPerf
Gateway ad altri DBMS Oracle, Sybase, IMS, DB2
Protocollo 2PC Si, presumed abort
Internet ESQL or 4GL CGI Interface Kit
La maggior parte dei sistemi Unix, Windows NT, Windows 95
Microsoft SQL Server originated from the porting of Sybase SQL Server to the Microsoft platform, retaining many architectural and syntactical similarities between the two systems However, the implementation of specific features varies significantly In recent versions, Microsoft has focused on integrating the DBMS with the BackOffice suite, resulting in a product that is vastly different from its original version.
Poiché Microsoft SQL Server gira solo sul sistema operativo Windows
The integration of the DBMS and the operating system at a lower level enhances performance while simplifying administration and management tasks This seamless integration also promotes better collaboration with other system components.
Update sulle viste (con opzione check)
Tipi dati definiti dall’utente Si
Struttura delle tabelle Nessuna scelta
Informazioni per il Tuning Coefficiente di riempimento, allocazione
Livello di Lock Database, tabella, pagina, riga
ANSI SQL Entry-Level SQL-92
Cursori Forward, backward, relativi, assoluti
API ESQL, DBLIB, Distributed Management Objects,
Tool Enterprise Manager, Performance Monitor
Backup parziale e Recovery Per tabella
Internet Internet Information Server in Windows NT
One of the key decisions in developing an information system is whether to store data in a centralized mainframe database or to utilize smaller departmental servers closer to the users.
Storicamente le grosse quantità di dati sono sempre state tenute sui mainframe, ma oggi c’è grande disponibilità di potenze di calcolo anche su piattaforme più piccole.
Modern applications demand enhanced performance and user-friendliness, necessitating the ability to access data from anywhere within an organization Design decisions must consider the optimal storage locations for quick data retrieval and the configuration of applications and databases across various platforms to ensure seamless interaction.
IBM DB2 che è sempre stato conosciuto come DBMS per mainframe, ha anch’esso seguito questa evoluzione, subendo il downsizing dal mainframe al server dipartimentale, e recentemente anche su PC.
Limitate, ad eccezione del cascade, set null
Update sulle viste (con opzione check)
Si, incluso le viste per union
Tipi dati definiti dall’utente Si
Tipi dati aggiuntivi Large object
Struttura delle tabelle Nessuna scelta
Allocazione tavole ed indici, coefficiente e ratio cluster
Livello Row-based, set-based
Livello di Lock Database, tabella, pagina, riga
ANSI SQL Entry-Level SQL-92
Tool Database Director, Visual Explain, Performance
DBMS Oracle, Sybase, Informix, MS SQL Server
Sistemi La maggior parte dei sistemi Unix, Windows NT,
Operativi VAX VMS, Windows 95, OS/2, Macintosh
In the early 1990s, Ingres was one of the most technologically advanced relational database management systems (DBMS), alongside Sybase and Interbase, incorporating features that competitors would not adopt until much later.
Relational Technologies Inc., the company behind Ingres and founded by Professor Michael Stonebraker of U.C Berkeley, underwent a restructuring to become Ingres Corp It was later acquired by ASK Corp and subsequently sold to Computer Associates International Inc (CA) Throughout this tumultuous journey, the evolution of the product experienced a slowdown.
Ora la CA ha ribattezzato il prodotto come CA-OpenIngres, aggiungendo quelle funzionalità e caratteristiche più volte attese nel passato.
Scheda Tecnica CA-OPEN INGRES
Update sulle viste (con opzione check)
Tipi dati definiti dall’utente Si
Tipi dati Byte, byte varying, long byte, long varchar, aggiuntivi money, spatial
Struttura delle tabelle B-tree, hash, heap, ISAM
Struttura degli indici B-tree, hash, ISAM
Allocazione tavole ed indici, coefficiente di riempimento, pre-allocazione
Esterne No (Eventi nel database)
Eventi Alerters su eventi nel Database
Livello di Lock Database, tabella, pagina
ANSI SQL Entry-Level SQL-92
API ESQL, TP/XA, ODBC
Backup parziale e Recovery Per tabella
DB2, Datacom, IMS, IDMS, VS AM, Oracle, RDB, Allbase, Informix, Oracle, Sybase
Formato Colonne 2008, eccetto BLOB 2GB
La maggior parte dei sistemi Unix, Windows NT, VAX VMS, Windows 95 (CA-
SCENARIO TECNOLOGICO: AMBIENTI DI SVILUPPO WEB
D ESCRIZIONE DELL ’ AREA TECNOLOGICA
La tecnologia Web costituisce attualmente la principale area tecnologica di investimento in ricerca e sviluppo dell'Information Technology.
The drive towards this technological area is fueled by the explosion of the Internet and the shift of business information processing towards Intranet and Web solutions These solutions are designed to be open to the external world and are based on standardized methods for creating internal networks.
Since the launch of the first web browsers in 1994, the consumer market for the World Wide Web has expanded to 40 million users today As businesses have only begun to explore the vast potential of the Internet, it is projected that the user base will reach 200 million by the year 2000.
The Intranet market is expected to experience significant growth, with the Gartner Group predicting that by 1998, 50% of large enterprises will install Intranet servers, resulting in a market valued at approximately $8 billion.
Le applicazioni web possono essere raggruppate in due macro-tipologie:
applicazioni statiche (dead web), che utilizzano esclusivamente gli standard HTML e HTTP per realizzare banche dati multi-mediali facilmente accessibili via internet, senza possibilità di effettuare attività dinamiche on-line;
applicazioni dinamiche (live web), che consentono di implementare logiche applicative interattive tipiche delle tradizionali applicazioni client-server
Gran parte delle attuali applicazioni dinamiche sono basate sulla tecnologia CGI (Common Gateway Interface), che e' stato il primo tentativo per lo sviluppo di applicazioni dinamiche per il WEB.
CGI-based applications are developed using third-generation languages such as C, C++, and scripting languages These applications operate as processes triggered by the Web Server, functioning outside the server's memory and process space, and deliver dynamic content to the browser via HTTP.
I limiti di CGI sono la scarsa scalabilita' e le ridotte prestazioni: esso, infatti,
e' poco scalabile poiche' richiede un processo per ogni client, per cui l'applicazione puo' scalare solo con significativi investimenti nell'hardware;
ha prestazioni ridotte perche' ogni richiesta HTTP porta al lancio e all'esecuzione di un processo.
Microsoft's proprietary API (ISAPI) and Netscape's API (NSAPI) address the limitations of CGI by allowing applications to access web server services more efficiently By running in the same process space as the web server, these APIs enhance performance through a shared process model.
The demand for scalable, high-performance, and robust applications to support the impressive developments of the Internet and Intranet is driving significant advancements in web technologies These innovations aim to make the localization of applications and data seamless, regardless of whether they are distributed across multiple servers located inside or outside the corporate network.
Le nuove tecnologie riferite a questa area hanno le loro fondamenta su una architettura client/server a 3 livelli o multilivello (3 tier o multi-tier architecture)
The three-tier architecture involves adding an additional server layer to the traditional two-tier client/server model, which typically consists of a client directly accessing a database server This enhanced structure aims to achieve superior performance, connectivity, flexibility, and scalability In the three-tier architecture, multiple second-level servers run application modules and connect to several third-level database servers The primary goal of this new architecture is to provide effective solutions for modern application needs.
"suddivisione del lavoro" lato server per accrescere la scalabilita'
The three-tier application model is founded on distributed object technology, which establishes an interoperability infrastructure among objects through an object bus This framework lays the groundwork for a novel component-based software development approach, utilizing components that can be reused from other projects or sourced from the market.
Le due principali architetture di oggetti distribuiti (ORB, Object Request Brokering) sono CORBA e COM:
CORBA (Common Object Request Broker) is an architecture established by the Object Management Group (OMG), a consortium of approximately 700 manufacturers representing the entire spectrum of the IT industry This standard defines the framework for interoperability while allowing independent software vendors to handle its implementation.
COM (Common Object Model) e' l'architettura di Microsoft, sponsorizzata dal consorzio di produttori Open Group, che valorizza tutti gli investimenti fatti nelle successive release dei sistemi operativi MS Windows.
Each technology generally serves the same purpose but employs its own approach However, only CORBA is fully independent of various operating platform implementations, whereas COM is closely tied to MS Windows platforms.
The architecture of distributed objects complements HTTP/CGI with ORB protocols, such as IIOP from Corba and OLE/DCOM from COM, at the middleware level This approach addresses the inefficiencies of HTTP/CGI in client interactions and enables communication between objects operating on multiple servers, thereby facilitating scalability and load balancing.
The competition between two distributed object architectures is particularly highlighted in the technology for creating components that reside on servers but can be downloaded and executed on clients These components enable dynamic application logic to be shifted to the client side, thereby reducing network traffic and enhancing performance This approach contrasts with CGI and APIs that deliver static HTML pages to web users.
Le due principali tecnologie per la realizzazione di componenti sono l'ambiente JAVA di Sun e la tecnologia Active X di Microsoft (in precedenza disponibile attraverso i controlli OLE o OCX).
Java, announced by Sun Microsystems in May 1995, has emerged as a powerful language and software platform for object-oriented development Its success is largely attributed to its portability across various platforms; Java compilers convert source code into platform-independent bytecode, which runs on the Java Virtual Machine (JVM) available on both client and server environments As a result, Java programs can be executed on any hardware equipped with the Java runtime environment.
Java Applets are executable Java bytecode files that run in a browser equipped with the Java Virtual Machine (JVM) on any client system, whereas Java Servlets are executed by the JVM on the server side.
Active X, basato sull'architettura COM, consente la realizzazione di componenti client e server scritti in vari linguaggi (Visual Basic, C++, Java).
ActiveX client components, unlike Java Applets, are downloaded in an executable binary format Typically, they target Intel machines that support the Win32 interface, such as Windows 95 or Windows NT However, Microsoft is planning to extend ActiveX support to other non-Windows platforms as well.
P RODOTTI DI MERCATO
Il mercato di questa nuova generazione di ambienti di sviluppo web è alimentato dalle seguenti tipologie di produttori:
produttori tradizionalmente impegnati nell'area degli ambienti di sviluppo client-server, che comprendono Microsoft, Sybase/PowerSoft, Unify, Fortè, Lotus;
grossi produttori di soluzioni applicative pacchettizzate, come Sap;
produttori di dbms relazionali, come Oracle, Informix, Ibm;
Recently established, agile, and aggressive companies have often outpaced major players in the Information Technology sector in this specific market area, including notable names like Netscape, Haht, NetDynamics, Next, Bluestone, and NetObjects.
Key players are engaged in a fierce competition to capture market share in an area now universally recognized as strategic for the Information Technology business.
Ogni produttore cerca di sfruttare tutte le armi di cui dispone:
Some manufacturers are leveraging their market shares in other technological areas by offering their existing clients web application development solutions that enhance the products that have traditionally been their flagship offerings.
altri produttori puntano a rinnovare completamente la loro offerta di prodotti, rifocalizzandola completamente sull'area tecnologica internet e intranet;
Companies that were early adopters of advanced technology and offer cutting-edge products are focused on strengthening their market presence by forming significant alliances and partnerships with major players in the IT industry.
Dall'offerta di ambienti dei produttori precedentemente identificati, sono stati selezionati un numero ristretto di prodotti per consentire l'analisi di dettaglio, sulla base dei seguenti criteri di selezione:
effettiva disponibilità commerciale e supporto tecnico in Italia;
supporto dei più diffusi linguaggi di programmazione;
assenza di linguaggi di programmazione proprietari esclusivi del prodotto;
referenze di società che utilizzano il prodotto per lo sviluppo di applicazioni web.
La selezione effettuata ha portato all'indentificazione dei seguenti prodotti:
I prodotti selezionati sono stati analizzati in termini di:
caratteristiche funzionali, prestazionali ed operative;
livello di integrazione con altri prodotti;
caratteristiche di fornitura e di supporto.
In particolare, le caratteristiche funzionali, prestazionali ed operative analizzate comprendono le seguenti categorie:
MODELLO APPLICATIVO Architettura, modalita' di strutturazione e di esecuzione dell'applicazione generata
MODALITA' DI SVILUPPO E LINGUAGGI Caratteristiche dell'ambiente di sviluppo, degli strumenti a disposizione per la realizzazione dell'applicazione e indicazione dei linguaggi utilizzati per la creazione delle componenti applicative.
Supporto per l'integrazione nell'applicazione in sviluppo, di componenti preesistenti
Integration with DBMS supports backend database integration, focusing on data access, the use of stored procedures, and the incorporation of DBMS design elements.
AUTHORING DI PAGINE WEB Funzioni e strumenti per la creazione di pagine web
INTERFACCIA CON HTTP SERVER Tipologie di interfacce supportate per l'interazione con http server
Supporto per la gestione dello stato delle sessioni e per il controllo degli accessi
SVILUPPO MULTIUTENTE Supporto al processo di sviluppo di gruppo
SUPPORTO PER L'APPRENDIMENTO Feature di ausilio all'apprendimento e all'utilizzo del prodotto
Caratteristiche per il test e l'installazione dell'applicazione
Supporto per la gestione dell'applicazione
GESTIONE DEL SITO WEB GENERATO Funzioni per la gestione del sito
Di seguito sono descritti i risultati dell'analisi di dettaglio effettuata sui prodotti selezionati.
This environment facilitates the development, authoring, deployment, and management of web applications for Microsoft target platforms It supports various programming languages while exclusively utilizing Microsoft server technologies The product allows integration with back-end DBMS through ODBC, and the generated application does not require a runtime server.
Caratteristiche funzionali, prestazionali ed operative
MODELLO APPLICATIVO Applicazioni client-server multilivello basate su componenti e architettura COM/DCOM
An Integrated Development Environment (IDE) offers a comprehensive workspace that seamlessly integrates with other Microsoft development environments such as Visual C++ 5.0, Visual J++ 1.1, and Visual Source Safe 5.0 It features a graphical representation of the object hierarchy that makes up the project, enhancing the programming experience.
Browser WEB integrato nell'IDE, basato su Internet Explorer 3.0, per il preview e il test di pagine web sviluppate , o possibilita' di integrazione con browser WEB di altri costruttori.
The project repository is accessible through a Microsoft HTTP server, which includes options such as Personal Web Server for Windows 95, Personal Web Services for Windows NT Workstation 4.0, and Internet Information Server 3.0 for Windows NT Server.
Generazione di pagine dinamiche attraverso le Active Server Page di IIS 3.0
Automated generation of HTML forms and corresponding logic in VBScript and JScript (both client-side and server-side) facilitates the management of data stored in backend DBMS This process is achieved through the Data Form Wizard and design-time ActiveX Control, enhancing efficiency in data handling and user interaction.
Generazione e test di istruzioni SQL (comprendenti anche il set di istruzioni DML) attraverso il Query Designer
Disponibilita' di applicazioni predefiniti e personalizzabili
Integration and reuse of Java applets, ActiveX controls, and Netscape plug-ins on the client side, along with server-side components developed in Java, Visual Basic, Visual C++, and other languages for creating COM components.
INTEGRAZIONE CON DBMS Accesso a DBMS via driver ODBC, orientato agli oggetti attraverso proprieta', metodi ed eventi degli Active Data Object (ADO)
Visione on-line di tutti gli elementi di un DBMS di back-end (inclusi i dati) attraverso Data View
Supporto di Stored Procedure preesistenti
Possibilita' di gestire connessioni contemporanee a piu' DBMS, integrando i dati in una stessa pagina web
AUTHORING DI PAGINE WEB Funzioni di authoring attraverso i tool integrati Front Page 97 Editor (editor html), Image Composer, Music Producer
Supporto di frame html basato sulle nuove specifiche 2.5D Layout del W3C
Corredo di template predefiniti e modificabili, basati sullo standard Cascading Style Sheets (in via di definizione da parte di W3C), per la definizione del layout delle pagine WEB.
Gestione dello stato delle sessioni attraverso le Active Server Page (per il controllo di variabili e connessioni a database di utenti distinti)
Conformita' al modello di sicurezza e controllo degli accessi propri dei dominiWindows NT
SVILUPPO MULTIUTENTE Gestione nativa di progetti multiutente con possibilita' di controllo delle versione e del sorgente attraverso l'integrazione nell'IDE di Source Safe 5.0
Disponibilita' di applicazioni esemplificative e di help on line estesi
Funzionalita' per il deployment dell'applicazione WEB
Disponibilita' del tool Microsoft Personal Web Server, per lo sviluppo e il test dell'applicazione nella piattaforma di sviluppo
Amministrazione dell'esecuzione delle componenti applicative lato server, attraverso il prodotto addizionale Microsoft Transaction Server 1.0, che consente maggiori performance, scalabilita' e supporto di transazioni che coinvolgono uno o piu' componenti
Visualizzazione grafica e gestione del sito WEB in produzione e funzioni per la riparazione di link errati e per la pubblicazione incrementale attraverso meccanismi drag and drop.
Possibilita' di controllare le versioni delle componenti applicative del sito WEB in produzione attraverso il tool addizionaleSource Safe.
Applet Java Si, come integrazione
Servlet Java Si, come integrazione
Visual Basic Si, come integrazione
Api native di DBMS No
Livello di Integrazione con altri Prodotti
Integrazione nativa con Source Safe, Visual J++, Visual C++
Integrazione con browser web e tool di authoring html di altri costruttori
Integrazione con DBMS via ODBC
Integrazione con Microsoft Transaction Server, per l'amministrazione delle componenti applicative lato server
Sistema Operativo Windows 95, Windows NT Workstation
Memoria Centrale 16 MB per Windows 95, 24 MB per
Altri requisiti drive CD Rom, monitor SVGA, mouse
Piattaforma di Sviluppo: SERVER (può essere co-residente al client)
Sistema Operativo Windows 95, Windows NT Workstation
HTTP server Personal Web Server (Windows 95)
Peer Web Services (Windows NT WS)
Internet Information Server 3.0 (NT Server)
Altri requisiti drive CD Rom, monitor SVGA, mouse
Browser con supporto delle tecnologie adottate per lo sviluppo, lato client
Sistema Operativo Windows 95, Windows NT
HTTP server Personal Web Server
Internet Information Server 3.0 (NT Server)
Altri requisiti drive CD Rom, monitor
Browser con supporto delle tecnologie adottate per lo sviluppo, lato client
Sistema Operativo Windows 95, Windows NT
Software di Amministrazione Client Interdev
Memoria Centrale 16 MB per Windows 95, 24 MB per
Altri requisiti drive CD Rom, monitor SVGA, mouse
Il prodotto è stato appena rilasciato, ma si posiziona come uno degli ambienti di sviluppo per applicazione WEB più potente, completo e facile da usare (rispetto alla categoria di funzionalità)
Microsoft is poised to capture a significant market share due to its strong focus on developing new products and strategic initiatives centered around internet and intranet technologies.
Caratteristiche di fornitura, supporto pre e post-vendita
DISTRIBUTORE Rete di distribuzione MICROSOFT ITALIA
COSTO Il prodotto costa 499 dollari, mentre i tool addizionali SOURCE SAFE 5.0 e VISUAL J++ 1.0 costano rispettivamente
499 dollari e 99 dollari (i costi si riferiscono alla singola licenza utente fruibile da una stazione di lavoro)
esistono politiche di upgrade da altri prodotti microsoft e poliche di competitive upgrade, oltre a tariffe per il mondo educational
SERVIZI DI SUPPORTO il supporto tecnico è assicurato dai principali servizi MICROSOFT (siti WEB di supporto e possibilità di sottoscrivere contratti a pagamento per l'assistenza tecnica di famiglie di prodotti)
disponibilità di prodotti di formazione e addestramento su CD (MICROSOFTMastering Series), in particolare due prodotto del costo di 99 dollari cadauno
The environment is designed for the development, deployment, and management of web applications that access Informix DBMS The application components are created using an extended HTML language and are managed by the Application Builder within a repository based on Informix DBMS To run the application, two runtime modules, WebDriver and WebExplode, are included in the package.
Caratteristiche funzionali, prestazionali ed operative
MODELLO APPLICATIVO Applicazioni client-server a 3 livelli
Repository di oggetti (componenti applicative) basato su dbms Informix, gestito dall'Application Builder e accessibile mediante un web browser
Gli oggetti sono pagine html (application page) con applet Java, documenti elettronici in vari formati (Word, PowerPoint, Adobe), oggetti multimediali (immagini, audio, video)
The article provides a set of instructions, including HTML extensions such as meta-tags, functions, variables, and conditional statements, which developers store in hidden fields within HTML pages These instructions enable the creation of dynamic pages that retrieve multimedia information from a back-end Informix database.
The development of objects occurs independently of product support; their integration into the application logic and the data stored in the DBMS is achieved through HTML extensions.
Le estensioni html sono processate a run-time dai moduli WebDriver e WebExplode, attivati dall'http server
Possibilita' di condividere gli oggetti del progetto attraverso l'Application Builder, mediante la definizione di user- define tags, riutilizzabili in una pagina html attraverso il formato SGML