org.apache.flink.table.catalog

Interface Constraint

All Known Implementing Classes:

UniqueConstraint

@PublicEvolving
public interface Constraint

Integrity constraints, generally referred to simply as constraints, define the valid states of SQL-data by constraining the values in the base tables.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Constraint.ConstraintType Type of the constraint.

Method Summary

Modifier and Type	Method and Description
String	asSummaryString() Prints the constraint in a readable way.
String	getName()
Constraint.ConstraintType	getType() Tells what kind of constraint it is, e.g.
boolean	isEnforced() Constraints can either be enforced or non-enforced.

Method Detail

getName

String getName()

isEnforced

boolean isEnforced()

Constraints can either be enforced or non-enforced. If a constraint is enforced it will be checked whenever any SQL statement is executed that results in data or schema changes. If the constraint is not enforced the owner of the data is responsible for ensuring data integrity. Flink will rely the information is valid and might use it for query optimisations.

getType

Constraint.ConstraintType getType()

Tells what kind of constraint it is, e.g. PRIMARY KEY, UNIQUE, ...

asSummaryString

String asSummaryString()

Prints the constraint in a readable way.