Quick Beginnings

Chapter 3. What's New in DB2 Version 5?

Version 5 of DB2 Universal Database is the follow-on product to DB2 Version 2 and Database Server Version 4, and offers many new features and enhancements. This section describes some of the major changes for this version, and points you to sources of more information in the DB2 library. The numerous enhancements include:

Exploitation of symmetric multiprocessors (SMP) for improved scalability and performance

DB2 now exploits the ability of an SMP system to share resources across multiple processors, performing your SQL queries more quickly. Utilities like LOAD, BACKUP, and RESTORE also take advantage of the multiprocessor environments.

For more information on parallelism, refer to the Administration Guide. The utilities are described in more detail in the Command Reference.

New graphical tools that make it easy to install, configure, and administer DB2 databases

From the Control Center on OS/2, Windows 95, and Windows NT platforms, you can accomplish just about any administrative task. A number of SmartGuides walk you through common tasks, such as configuring communications and creating tables. You can also use the graphical tools from an OS/2, Windows 95, or Windows NT client to administer DB2 servers on UNIX platforms. Improved online help and the Information Center help you easily find the information you need to use DB2. For more details, refer to Chapter 2. "About DB2 Universal Database" or try out the Control Center.

Extensions to SQL, including support for online analytical processing

With the new CUBE and ROLLUP aggregations, you can now create "super groups", like "overall total" and "cross-tabulation", for improved online analytical processing. You can also perform outer joins, rename tables, define unique constraints on tables, and create your own table functions. DB2 has refined its authorization support, so you can grant authority at a more granular level; you can also create schemas to grant various attributes and privileges. For more details on these and other new SQL features, refer to the SQL Reference .

Performance, capacity, and memory improvements

DB2 now provides global caching for SQL statements, creating a public repository that improves performance. You can create multiple buffer pools of various sizes to better control the data in memory. Client/server communications are more efficient, crash and rollforward recovery are faster, and LOAD features numerous performance enhancements. For information on how to exploit these enhancements, refer to the Administration Guide.

Security enhancements, including support for Open Software Foundation's Distributed Computing Environment (DCE)

You can now use the DCE architecture to manage users, passwords, and groups more easily, and authenticate users more securely. DB2 also provides a "Trusted Clients" option so you can choose whether to trust all clients or only those that come from an operating system with inherent security. Security considerations are described more fully in the Administration Guide.

Additional support for communicating with host databases using DB2 Connect and the Distributed Relational Database Architecture (DRDA)

You can now communicate with host systems using TCP/IP, as well as SNA. In addition, DB2 servers can accept requests from host systems using TCP/IP, meaning you can use your DB2 workstation server as an application server to the host. On OS/2 and UNIX platforms, you can perform two-phase commits using DB2 Connect and TCP/IP; if you're using SNA, you can invoke a two-phase commit involving both the host and the DB2 server. For more details about connecting to host databases, refer to the DB2 Connect Enterprise Edition Quick Beginnings and DB2 Connect User's Guide.

Enhancements to application programming for DB2

The DB2 Call Level Interface (DB2 CLI) now reflects the Microsoft Open Database Connectivity 3.0 specifications, meaning that you can connect to DB2 databases from ODBC 3.0 applications. Additions to user-defined functions include scrollable cursors and the UCT_UNIQUE function to return a unique value to use in a table column. You can also invoke external UDFs that are methods of OLE automation servers. For more details on these and other improvements, refer to the CLI Guide and Reference, Embedded SQL Programming Guide, and API Reference.

There are many other new features, from the DB2 Governor, which you can use to handle application behavior, to table space features, such as recovery to a point in time and selective restore, to improved error messages. For a comprehensive list of what's new, see the Information Center.

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