DB2 & IMS

FlashCopy is an IBM microcode-based technology that comes as an add-on feature to the more advanced IBM DASD subsystems. Other DASD manufacturers typically have similar capabilities under different names. This technology lets the DASD subsystem handle some of the data movement task rather than relying on the operating system or programs. FlashCopy is a useful utility for backing up databases and moving large volumes of data quickly at a DASD volume level. FlashCopy Version 2 introduces data set level copy…

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Open Access to IMS With ODBA and OTMA

IMS, IBM strategic database software using hierarchical database technology to support high-transaction volumes, provides reliable and high throughput for more than 95 percent of Fortune 1000 companies. IMS is comprised of two major components: the Database Manager (IMS DB) and Transaction Manager (IMS TM). Together, they create a complete online database transaction- processing environment, providing continuous data availability and data integrity…

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Stored procedures have been around since DB2 Version 4 and have seen a few changes since their inception. Version 8 (V8) brings a new requirement to using stored procedures: Workload Manager (WLM). In the past, using WLM to manage stored procedure address spaces was optional. It’s worth taking a quick look at how stored procedures work with WLM so we can understand the benefits. We may want to begin the conversion of our stored procedures from DB2 managed address spaces before we migrate to V8 to take advantage of the WLM environment…

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DB2 V8 offers a useful new feature known as Materialized Query Tables (MQTs). Though not exclusively for data warehousing, MQTs can improve the elegance and efficiency of DB2-based data warehouses. An MQT can be thought of as a view that has been materialized—that is, a view whose data is physically stored instead of virtually accessed when needed. Each MQT is defined as an SQL query, but the MQT actually stores the query results as data. Subsequent user queries that require the data can use the MQT data instead of re-accessing it from the base tables. By materializing complex queries into MQTs and then accessing the materialized results, the cost of materialization is borne only once, when the MQT is refreshed…

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Using RACF To Control Access To DB2 Objects

Ever since the release of DB2 Version 5 and OS/390 Version 2, Release 4, you have had a choice of how you protect your DB2 resources: native DB2 controls or RACF. An effective DB2 security implementation using RACF requires close coordination between your DBA team and your security implementation (RACF) team. This article describes the security mechanisms available with RACF…

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