org.apache.flink.table.api.constraints

Class UniqueConstraint

java.lang.Object

org.apache.flink.table.api.constraints.UniqueConstraint

All Implemented Interfaces:

Constraint

@PublicEvolving
public final class UniqueConstraint
extends Object

A unique key constraint. It can be declared also as a PRIMARY KEY.

See Also:

ConstraintType

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.table.api.constraints.Constraint

Constraint.ConstraintType

Method Summary

Modifier and Type	Method and Description
String	asSummaryString() Returns constraint's summary.
boolean	equals(Object o)
List<String>	getColumns() List of column names for which the primary key was defined.
String	getName()
Constraint.ConstraintType	getType() Tells what kind of constraint it is, e.g.
int	hashCode()
boolean	isEnforced() Constraints can either be enforced or non-enforced.
static UniqueConstraint	primaryKey(String name, List<String> columns) Creates a non enforced ConstraintType#PRIMARY_KEY constraint.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

primaryKey

public static UniqueConstraint primaryKey(String name,
                                          List<String> columns)

Creates a non enforced ConstraintType#PRIMARY_KEY constraint.

getColumns

public List<String> getColumns()

List of column names for which the primary key was defined.

getType

public Constraint.ConstraintType getType()

Description copied from interface: Constraint

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

asSummaryString

public final String asSummaryString()

Returns constraint's summary. All constraints summary will be formatted as

 CONSTRAINT [constraint-name] [constraint-type] ([constraint-definition])

 E.g CONSTRAINT pk PRIMARY KEY (f0, f1)
 

equals

public boolean equals(Object o)

hashCode

public int hashCode()

getName

public String getName()

Specified by:

getName in interface Constraint

isEnforced

public boolean isEnforced()

Description copied from interface: Constraint

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.

Specified by:

isEnforced in interface Constraint

toString

public String toString()

Overrides:

toString in class Object