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Implementing Siebel Business Applications on DB2 UDB for z/OS > Customizing a Development Environment > How Siebel Implements LONG Columns on DB2 for z/OSSiebel Business Applications uses LONG columns on RDBMS tables to store arbitrarily long character data up to 16350 characters. Examples include scripts, emails, notes, and descriptions. On all RDBMS platforms, except DB2 for z/OS, the size of LONG columns is fixed and is independent of the size of the table space in which the table is defined. On DB2 for z/OS, a LONG column defined in the Siebel Schema is mapped to a LONG VARCHAR column. The size of a LONG VARCHAR column on DB2 for z/OS varies depending on two factors:
You can estimate the size of the LONG VARCHAR column by calculating the size of the table space minus the size of all non-LONG VARCHAR columns; the LONG VARCHAR column takes up the remainder of the space in the table space. For example, a table containing one LONG VARCHAR column, defined in a 16 KB table space, with a combined byte size for non-LONG VARCHAR columns of 5 KB, results in the LONG VARCHAR column having a size of about 11 KB. For more information on calculating the size of LONG VARCHAR columns, refer to the vendor documentation on the IBM Web site How Siebel Business Applications Store Tables with LONG VARCHAR ColumnsIf Siebel Business Applications created all LONG VARCHAR columns on DB2 for z/OS with a length of 16,350 characters, this would effectively force all tables to a 32 KB table space; this table space size increases buffer pool storage requirements. To minimize the number of tables created in 32 KB table spaces, during the Siebel installation process, tables with LONG VARCHAR columns are created in an 8 KB table space by default. Siebel Business Applications assume that LONG VARCHAR columns have a logical length of 4046 bytes, which forces the table to be created in an 8 KB table space. However, some of the larger tables with LONG VARCHAR columns are created in 16 KB table spaces. NOTE: Although Siebel Business Applications set the LONG VARCHAR column to have a logical length of 4046 bytes, the physical length is not specified in the By taking this approach, almost all aspects of the Siebel application function without problems. However, if your implementation involves a usage scenario in which very large notes, descriptions, emails, or other items up to 16, 350 characters in length are stored, then you need to resolve this by considering one of the following choices:
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