SAP with Microsoft SQL Server 2005: Best Practices for High Availability, Maximum Performance, and Scalability27
SAP database schema
SAP business applications database schema can include up to 45,000 tables, depending on the SAP product.
Clustered and nonclustered indexes. Nearly all tables use the primary key constraint of SQL Server 2005. This results in a clustered index over the fields of the primary key. No other constraints are used. Nearly 20 to 25 percent of the tables have one or more nonclustered indexes. The order of deployed, nonclustered indexes can be changed. In addition, a clustered index can be made nonclustered and conversely, a nonclustered index can become a clustered index.
Additional indexes. In a standard deployment, a database table has a maximum of seven indexes. However, customers can create additional indexes to suite their customization of SAP business logic or customer-coded business logic. Indexed views or indexes on computed columns cannot be created outside of SAP.
Index column order. The order of index columns is nonstandard, with the most unselective columns first. The order of index columns follows the order of columns in the table. Except for the primary key index, the order of the columns is free and can be changed (although this is usually unnecessary). The order of the columns in the primary key index may not be changed, because an ABAP construct might rely on the defined order of the primary key.
Index creation. Creating indexes or changing existing indexes must be performed over the SAP Index Maintenance Transaction to guarantee that SAP can export the index.
Collation and code page
All SAP products use code page (cp) 850_BIN or 850_BIN2 as the server code page with the exception of the SAP® Mobile Sales client and SAP® Business One. SQL Server 2005 must be installed with cp850_BIN2.
When upgrading a database from SQL Server 2000 to SQL Server 2005, attach the database using cp850_BIN2. For more information, see SAP OSS Note 6000279.
SQL Server 2005 Setup screen
The sample in Figure 11 shows the code page selection screen during a SQL Server 2005 installation. For SAP installations with SQL Server 2005, the code page selection should be Binary Order based on code point comparison, for use with 850 (Multilingual) as shown in Figure 11. Do not choose any other option and do not choose Binary sort order for cp850.
9 The SAP OSS Notes are only available to registered customers of SAP AG.
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