Available in versions: Dev (3.20) | Latest (3.19) | 3.18 | 3.17 | 3.16 | 3.15 | 3.14 | 3.13 | 3.12 | 3.11 | 3.10
Unique constraints
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
A candidate key that is not ideal for a Primary key should still be declared UNIQUE
to enforce uniqueness, as well as for query performance reasons. In jOOQ, this can be done with the following approaches:
// Create a new table with columns and unnamed constraints create.createTable("table") .column("column1", INTEGER) .column("column2", INTEGER) .column("column3", INTEGER) .unique("column1") .unique("column2", "column3") .execute(); // Equivalent to the above create.createTable("table") .column("column1", INTEGER) .column("column2", INTEGER) .column("column3", INTEGER) .constraints( unique("column1"), unique("column2", "column3") ) .execute(); // Create a new table with columns and named constraints (recommended if you want to alter the constraint) create.createTable("table") .column("column1", INTEGER) .column("column2", INTEGER) .column("column3", INTEGER) .constraints( constraint("uk1").unique("column1"), constraint("uk2").unique("column2", "column3") ) .execute();
Dialect support
This example using jOOQ:
createTable("table") .column("column1", INTEGER) .constraints( constraint("uk").unique("column1") )
Translates to the following dialect specific expressions:
Access, DB2, Firebird, Hana, Teradata
CREATE TABLE table ( column1 integer, CONSTRAINT uk UNIQUE (column1) )
ASE, Sybase
CREATE TABLE table ( column1 int NULL, CONSTRAINT uk UNIQUE (column1) )
Aurora MySQL, Aurora Postgres, Derby, DuckDB, Exasol, H2, HSQLDB, MariaDB, MemSQL, MySQL, Postgres, Redshift, SQLServer, SQLite, Vertica, YugabyteDB
CREATE TABLE table ( column1 int, CONSTRAINT uk UNIQUE (column1) )
BigQuery
CREATE TABLE table ( column1 int64 )
ClickHouse
CREATE TABLE table ( column1 Nullable(integer) ) ENGINE Log()
CockroachDB
CREATE TABLE table ( column1 int4, CONSTRAINT uk UNIQUE (column1) )
Informix
CREATE TABLE table ( column1 integer, UNIQUE (column1) CONSTRAINT uk )
Oracle, Snowflake
CREATE TABLE table ( column1 number(10), CONSTRAINT uk UNIQUE (column1) )
SQLDataWarehouse
CREATE TABLE table ( column1 int, CONSTRAINT uk UNIQUE (column1) NOT ENFORCED )
Trino
CREATE TABLE table ( column1 int )
Generated with jOOQ 3.20. Translate your own SQL on our website
Feedback
Do you have any feedback about this page? We'd love to hear it!