Progress
DataServer for
Microsoft SQL Server
Guide
Data Source Record Locking
In a DataServer application, SQL Server™ handles all of its own locking issues. The Progress 4GL locking rules are modified when you access information from an MSS data source. As a result, the Progress phrases NO–LOCK and SHARE–LOCK have isolation-level dependencies. The EXCLUSIVE-LOCK behaves the same in SQL Server™ as in Progress.
Table 2–4 provides data source specific comparisons.
The Merant drivers provide for transaction isolation levels. In a multi-user configuration, you can isolate users from each other in your data source by setting the isolation level. In your Progress schema holder, use the –Dsrv TXN_ISOLATION,n connection parameter (where n = 1, 2, 4, or 8) to set the isolation level in ODBC. See the Microsoft ODBC Programmer’s Reference and the SQL Server™ documentation for more information.
NOTE: SQL Server™ might use page-level or table-level locking rather than record-level locking, if its optimizer determines this is the best choice. This can affect data access when two or more users attempt to read or update different records that are on the same page. See your SQL Server™ documentation for details.
Table 2–5: N Values in the –Dsrv Parameter Value Meaning 1 Read uncommitted 2 Read committed 4 Repeatable read 8 SerializableTable 2–5 shows the possible –Dsrv TXN_ISOLATION,n values with the respective meaning.
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