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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™.
TRUNCATE statementUse the TRUNCATE statement to quickly delete all rows from a local table and free the associated storage space. You can optionally reserve the space for the same table and its indexes. Only HCL OneDB™ supports this implementation of the TRUNCATE statement, which is an extension to the ANSI/ISO standard for SQL.
The AM_TRUNCATE Purpose Function

The AM_TRUNCATE Purpose Function

HCL OneDB™ provides built-in am_truncate purpose functions for its primary access methods that support TRUNCATE operations on columns of permanent and temporary tables. It also provides a built-in am_truncate purpose function for its secondary access method for TRUNCATE operations on B-tree indexes.

For the TRUNCATE statement to work correctly in a virtual table interface (VTI) table requires a valid am_truncate purpose function in the primary access method for the data type of the VTI table. To register a new primary access method in the database, use the CREATE PRIMARY ACCESS_METHOD statement of SQL:

CREATE PRIMARY ACCESS_METHOD vti(
  AM_GETNEXT  = vti_getnext
  AM_TRUNCATE = vti_truncate
  ...);

You can also use the ALTER ACCESS_METHOD statement to add a valid am_truncate purpose function to an existing access method that has no am_truncate purpose function:

ALTER ACCESS_METHOD abc (ADD AM_TRUNCATE = abc_truncate);

In these examples, the vti_truncate and abc_truncate functions must be routines that support the functionality of the AM_TRUNCATE purpose option keyword, and that were previously registered in the database by the CREATE FUNCTION or CREATE ROUTINE FROM statement.