Postgresql unique index multiple columns
When you add a UNIQUE constraint to a column or a group of columns, PostgreSQL will automatically create a unique index on the column or the group of columns.,You can do that in pure SQL. Create a partial unique index in addition to the one you have: CREATE UNIQUE INDEX ab_c_null_idx ON my_table (id_A, ...
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 Postgresql unique index multiple columns 相關參考資料
PostgreSQL UNIQUE Index
Note that only B-tree indexes can be declared as unique indexes. When you define an UNIQUE index for a column, the column cannot store multiple rows with the ... https://www.postgresqltutorial PostgreSQL UNIQUE Constraint
When you add a UNIQUE constraint to a column or a group of columns, PostgreSQL will automatically create a unique index on the column or the group of columns. https://www.postgresqltutorial PostgreSQL multi-column unique constraint and NULL values
You can do that in pure SQL. Create a partial unique index in addition to the one you have: CREATE UNIQUE INDEX ab_c_null_idx ON my_table (id_A, ... https://dba.stackexchange.com Documentation: 9.1: Unique Indexes - PostgreSQL
When an index is declared unique, multiple table rows with equal indexed values are not allowed. Null values are not considered equal. A multicolumn unique ... https://www.postgresql.org Documentation: 9.6: Multicolumn Indexes - PostgreSQL
An index can be defined on more than one column of a table. ... The only reason to have multiple BRIN indexes instead of one multicolumn BRIN index on a ... https://www.postgresql.org Documentation: 12: 11.6. Unique Indexes - PostgreSQL
Null values are not considered equal. A multicolumn unique index will only reject cases where all indexed columns are equal in multiple rows. PostgreSQL ... https://www.postgresql.org Documentation: 13: 11.6. Unique Indexes - PostgreSQL
Null values are not considered equal. A multicolumn unique index will only reject cases where all indexed columns are equal in multiple rows. PostgreSQL ... https://www.postgresql.org Documentation: 9.0: Unique Indexes - PostgreSQL
When an index is declared unique, multiple table rows with equal indexed values are not allowed. Null values are not considered equal. A multicolumn unique ... https://www.postgresql.org Documentation: 11: 11.6. Unique Indexes - PostgreSQL
Null values are not considered equal. A multicolumn unique index will only reject cases where all indexed columns are equal in multiple rows. PostgreSQL ... https://www.postgresql.org In Postgresql, force unique on combination of two columns
2013年1月8日 — Create unique constraint that two numbers together CANNOT together be repeated: ALTER TABLE someTable ADD UNIQUE (col1, col2). https://stackoverflow.com |