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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™.
CREATE TABLE statementUse the CREATE TABLE statement to create a new permanent table in the current database.
Column definitionUse the column definition segment of the CREATE TABLE statement to declare the name and data type (and optionally the default value and the constraints or the security label) of a single column of the new table.
Single-Column Constraint FormatUse the Single-Column Constraint format to define and declare the name of at least one constraint on a single column, and to specify the mode of each constraint.
CHECK Clause
Using a Search Condition

Using a Search Condition

The search condition that defines a check constraint cannot contain the following elements: user-defined routines, subqueries, aggregates, host variables, or rowids. In addition, the search condition cannot contain the following built-in variant functions: CURRENT, SYSDATE, USER, CURRENT_USER, SITENAME, DBSERVERNAME, or TODAY.

When you specify a date value in a search condition, make sure you specify four digits for the year, so that the DBCENTURY environment variable has no effect on the condition. When you specify a two-digit year, the DBCENTURY environment variable can produce unpredictable results if the condition depends on an abbreviated year value. For more information about DBCENTURY, see the HCL OneDB™ Guide to SQL: Reference.

More generally, the database server saves the settings of environment variables from the time of creation of check constraints. If any of these settings are subsequently changed in a way that can affect the evaluation of a condition in a check constraint, the new settings are disregarded, and the original environment variable settings are used when the condition is evaluated.

With a BYTE or TEXT column, you can check for NULL or not-NULL values. This constraint is the only constraint allowed on a BYTE or TEXT column.