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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.
Constraint Definition
Declaring a Constraint Name

Declaring a Constraint Name

The database server implements the constraint as an index. Whenever you use the single- or multiple-column constraint format to place a data restriction on a column, but without declaring a constraint name, the database server creates a constraint and adds a row for that constraint in the sysconstraints system catalog table.

The database server also generates an identifier and adds a row to the sysindices system catalog table for each new primary-key, unique, or referential constraint that does not share an index with an existing constraint. Even if you declare a name for a constraint, the database server generates the name that appears in the sysindices table. (The system catalog also includes a view on the sysindices table, called sysindexes, which also lists each component of a composite index.)

If you want, you can specify a meaningful name for the constraint. The name must be unique among the names of constraints and indexes in the database.

Constraint names appear in error messages having to do with constraint violations. You can use this name when you use the DROP CONSTRAINT clause of the ALTER TABLE statement.

You also specify a constraint name when you change the mode of constraint with the SET Database Object Mode statement or the SET Transaction Mode statement, and in the DROP INDEX statement for constraints that are implemented as indexes with user-defined names.

In an ANSI-compliant database, when you declare the name of a constraint of any type, the combination of the owner name and constraint name must be unique within the database.