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SQL programmingYou can use the HCL OneDB™ implementation of the SQL language to develop applications for HCL OneDB™ database servers.
Guide to SQL: SyntaxThe HCL OneDB™ Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the HCL OneDB™ dialect of the SQL language.
SQL statementsThis chapter describes the syntax and semantics of SQL statements that are recognized by HCL OneDB™.
SET ISOLATION statementUse the SET ISOLATION statement to define the degree of concurrency among processes that attempt to access the same rows simultaneously.
HCL OneDB™ Isolation Levels
Default Isolation Levels

Default Isolation Levels

The default isolation level for a particular database is established when you create the database according to database type. The following list describes the default isolation level for each database type.

Isolation Level: Database Type
Dirty Read: Default level in a database without logging
Committed Read: Default level in a logged database that is not ANSI compliant
Repeatable Read: Default level in an ANSI-compliant database

The default level remains in effect until you issue a SET ISOLATION statement. After a SET ISOLATION statement executes, the new isolation level remains in effect until one of the following events occurs:

You enter another SET ISOLATION statement.
You open another database that has a default isolation level different from the level that your last SET ISOLATION statement specified.
The program ends.

For a HCL OneDB™ database that is not ANSI-compliant, unless you explicitly set the USELASTCOMMITTED configuration parameter, the LAST COMMITTED feature is not in effect for the default isolation levels. The SET ENVIRONMENT statement or the SET ISOLATION statement can override this default and enable LAST COMMITTED for the current session.