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As data size and complexity continue to increase, efficient, reliable and secure data handling becomes critical. Leveraging DB2 temporary tables for report isolation can help optimize your data operations. Using temporary tables can not only improve your report performance but also provide data isolation which enhances data security and integrity.

Temporary tables in DB2, like in SQL Server 2016, SQL Server 2017, MySQL 5.7, and Azure SQL, are created and used for the duration of a session or the execution of a block of code. These tables can be created at runtime and can do all the operations that a normal table can do. But, once the session or block of code is completed, these tables are automatically dropped.

In terms of report generation, they offer the advantage of breaking down complicated queries into simpler parts. This can result in improved performance for complex reporting requirements. Let's take a look at the following DB2 code example:

-- DB2 code for creating a temporary table
DECLARE GLOBAL TEMPORARY TABLE SESSION.report_temp
( session_user VARCHAR(10),
  report_date DATE,
  report_data VARCHAR(255) )
ON COMMIT DELETE ROWS
NOT LOGGED
WITH REPLACE

In this example, a temporary table called report_temp is created in the SESSION schema. This table will be used to store report data temporarily for generating reports. The 'ON COMMIT DELETE ROWS' clause ensures that the data in the table are deleted whenever a commit operation occurs. This ensures that the data from different transactions do not mix, providing data isolation.

Furthermore, the ‘NOT LOGGED’ clause instructs DB2 not to log any operations performed on this table, thereby improving the performance. And the ‘WITH REPLACE’ clause allows the re-creation of the temporary table within the same unit of work if it already exists.

You can now populate the temporary table with data and use it for report generation. Here is an example:

-- DB2 code for inserting data into the temporary table
INSERT INTO SESSION.report_temp(session_user, report_date, report_data)
VALUES('User 1', CURRENT DATE, 'Sample Report Data')

In conclusion, leveraging temporary tables in DB2 for report isolation not only simplifies complex queries but also ensures data isolation and improved performance. Similar concepts and practices can be applied to other databases like SQL Server 2016, SQL Server 2017, MySQL 5.7, and Azure SQL, making them an essential tool for efficient data handling in any database management system.