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I need to drop a unique constraint from a postgresql table, but I didn't give it a name in the schema. Does anybody know, how to get the name of such a constraint, or how to drop it?
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SELECT conname FROM pg_constraint WHERE conrelid = (SELECT oid FROM pg_class WHERE relname LIKE 'tableName'); Also you can get it from pgAdmin in objects tree.
You can show unique constraints of a table in MySQL using information_schema. table_constraints.
What is a unique constraint in PostgreSQL? A unique constraint is a single field or combination of fields that uniquely defines a record. Some of the fields can contain null values as long as the combination of values is unique.
In PostgreSQL, the default constraint types are p , f , u , and c . The PRIMARY KEY is named by default with the table name, an underscore (' _ '), and ' pkey '.
That is something like (for single column constaint):
tableName_columnName_key To get constaint name write (in psql):
\d tableName or use pg_constraint system catalog:
SELECT conname FROM pg_constraint WHERE conrelid = (SELECT oid FROM pg_class WHERE relname LIKE 'tableName'); Also you can get it from pgAdmin in objects tree.
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