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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™.
ALTER FRAGMENT statementUse the ALTER FRAGMENT statement to change the distribution strategy or the storage location of an existing table or index. This statement is an extension to the ANSI/ISO standard for the SQL language.
INIT ClauseThe INIT clause of the ALTER FRAGMENT statement can define or modify the fragmentation strategy or the storage location of an existing table or an existing index.
FRAGMENT BY clause for indexesUse the FRAGMENT BY clause to redefine the storage distribution strategy of an index without redefining the index. The keywords FRAGMENT BY and PARTITION BY are synonyms in this context.
Fragmenting Unique and System Indexes

Fragmenting Unique and System Indexes

You can fragment unique indexes on a table that uses a round-robin or expression-based distribution scheme, but any columns referenced in the fragment expression must be indexed columns. If your index fragmentation strategy violates this restriction, the ALTER FRAGMENT INIT statement fails, and work is rolled back.

You might have an attached unique index on a table fragmented by Column A. If you attempt to use ALTER FRAGMENT INIT to change the table fragmentation to Column B, the statement fails because the unique index is defined on Column A. To resolve this issue, use the INIT clause on the index to detach it from the table fragmentation strategy and fragment it separately.

System indexes (such as those used in referential constraints and unique constraints) use user-defined indexes if the indexes exist. If no user-defined indexes can be used, system indexes remain nonfragmented and are moved to the dbspace where the database was created. To fragment a system index, create the fragmented index on the constraint columns and then use the ALTER TABLE statement to add the constraint.