Helper scripts to rename different types of T-SQL constraint names. Especially useful for fixing generated names across environments.

fix_generated_constraint.sql

-- rename DEFAULT constraints --
DECLARE @sql NVARCHAR(MAX) = N''
SELECT @sql +=
-- SELECT
       N'exec sp_rename ' + QUOTENAME(schemas.name + '.' + sys.default_constraints.name) + ', ''DF_' + sys.tables.name + '_' +
       sys.all_columns.name + ''';'
FROM sys.all_columns
INNER JOIN sys.tables ON all_columns.object_id = tables.object_id
INNER JOIN sys.schemas ON tables.schema_id = schemas.schema_id
INNER JOIN sys.default_constraints ON all_columns.default_object_id = default_constraints.object_id
WHERE schemas.name = 'YOUR-SCHEMA-NAME'
  AND sys.all_columns.default_object_id = default_constraints.object_id
EXEC sp_executesql @sql
GO

-- rename PRIMARY KEY constraints --
DECLARE @sql NVARCHAR(MAX) = N''
SELECT @sql +=
-- SELECT
       N'exec sp_rename ' + QUOTENAME(table_schema + '.' + CONSTRAINT_NAME) + ', ''PK_' + TABLE_NAME + ''';'
FROM information_schema.table_constraints
WHERE constraint_type = 'PRIMARY KEY'
  AND table_schema = 'YOUR-SCHEMA-NAME'
EXEC sp_executesql @sql
GO

-- rename FOREIGN KEY constraints --
DECLARE @sql NVARCHAR(MAX) = N''
SELECT @sql +=
-- SELECT
       N'exec sp_rename ' + QUOTENAME(s.name + '.' + fk.name) + ', ''FK_' + parent_tables.name + '_' + referenced_tables.name + '_' +
       parent_columns.name + ''';'
FROM sys.foreign_keys fk
JOIN sys.foreign_key_columns fkc ON fkc.constraint_object_id = fk.object_id
JOIN sys.tables parent_tables ON fk.parent_object_id = parent_tables.object_id
JOIN sys.tables referenced_tables ON fk.referenced_object_id = referenced_tables.object_id
JOIN sys.columns parent_columns ON fkc.parent_object_id = parent_columns.object_id AND fkc.parent_column_id = parent_columns.column_id
JOIN sys.schemas s ON s.schema_id = fk.schema_id
WHERE s.name = 'YOUR-SCHEMA-NAME'
EXEC sp_executesql @sql
GO