可用版本: Dev (3.21) | 最新 (3.20) | 3.19 | 3.18 | 3.17 | 3.16 | 3.15 | 3.14 | 3.13

ALTER TABLE .. DROP CONSTRAINT IF EXISTS

适用于 ✅ 开源版   ✅ 专业版   ✅ 企业版

DDL 语句中一个常见的子句是 IF EXISTS 子句,jOOQ 通常可以模拟它

方言支持

此示例使用 jOOQ

alterTable("t").dropConstraintIfExists("c")

翻译成以下特定方言的表达式

Aurora Postgres, CockroachDB, Databricks, H2, MariaDB, Postgres

ALTER TABLE t DROP CONSTRAINT IF EXISTS c

BigQuery, ClickHouse

ALTER TABLE t DROP PRIMARY KEY

DB2

BEGIN
  DECLARE CONTINUE HANDLER FOR SQLSTATE '42703' BEGIN END;
  DECLARE CONTINUE HANDLER FOR SQLSTATE '42704' BEGIN END;
  EXECUTE IMMEDIATE '
    ALTER TABLE t DROP CONSTRAINT c
  ';
END

Firebird

EXECUTE BLOCK
AS
BEGIN
  EXECUTE STATEMENT '
    ALTER TABLE t DROP CONSTRAINT c
  ';
  WHEN sqlcode -607 DO
    BEGIN END
END

Hana

DO BEGIN
  DECLARE EXIT HANDLER FOR SQL_ERROR_CODE 257 BEGIN END;
  DECLARE EXIT HANDLER FOR SQL_ERROR_CODE 260 BEGIN END;
  DECLARE EXIT HANDLER FOR SQL_ERROR_CODE 397 BEGIN END;
  EXECUTE IMMEDIATE '
    ALTER TABLE t DROP CONSTRAINT c
  ';
END;

Oracle

BEGIN
  EXECUTE IMMEDIATE '
    ALTER TABLE t DROP CONSTRAINT c
  ';
EXCEPTION
  WHEN others THEN
    IF sqlerrm LIKE 'ORA-00904%' THEN NULL;
    ELSIF sqlerrm LIKE 'ORA-02443%' THEN NULL;
    ELSE RAISE;
    END IF;
END;

SQLServer

BEGIN TRY
  EXEC sp_executesql N'
    ALTER TABLE t DROP CONSTRAINT c
  ';
END TRY
BEGIN CATCH
  IF error_number() NOT IN (4924, 3728, 3727, 1750, 15248) THROW;
END CATCH

YugabyteDB

DO $$
BEGIN
  ALTER TABLE t DROP CONSTRAINT c;
EXCEPTION
  WHEN SQLSTATE '42703' THEN NULL;
  WHEN SQLSTATE '42704' THEN NULL;
END $$

ASE, Access, Aurora MySQL, Derby, DuckDB, Exasol, HSQLDB, Informix, MemSQL, MySQL, Redshift, SQLDataWarehouse, SQLite, Snowflake, Sybase, Teradata, Trino, Vertica

/* UNSUPPORTED */
使用 jOOQ 3.21 生成。早期 jOOQ 版本的支持可能有所不同。 在我们的网站上翻译您自己的 SQL

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