如何在 postgresql 中正确实现软删除？

Question

在我的 postgres 9.3 数据库中，我有以下函数和触发器的组合来实现软删除功能：

ALTER TABLE "LIBN02"."trigger_test_1"
ADD COLUMN delete_ind integer

CREATE OR REPLACE FUNCTION trigger_test_1_soft_delete()  
  RETURNS trigger AS $$
    DECLARE
      command text := ' SET delete_ind = 1 WHERE uuid_col = $1';
    BEGIN
      EXECUTE 'UPDATE ' || "LIBN02"."trigger_test_1" || command USING OLD.uuid_col;
      RETURN NULL;
    END;
  $$ LANGUAGE plpgsql;

CREATE TRIGGER test_1_soft_delete_trigger  
  BEFORE DELETE ON "LIBN02"."trigger_test_1"
  FOR EACH ROW EXECUTE PROCEDURE trigger_test_1_soft_delete();

以上所有操作完成后，我运行以下删除语句：

DELETE FROM "LIBN02"."trigger_test_1"

我收到以下错误：

ERROR:  missing FROM-clause entry for table "LIBN02"
LINE 1: SELECT 'UPDATE ' || "LIBN02"."trigger_test_1" || command
                            ^
QUERY:  SELECT 'UPDATE ' || "LIBN02"."trigger_test_1" || command
CONTEXT:  PL/pgSQL function trigger_test_1_soft_delete() line 5 at EXECUTE

********** Error **********

ERROR: missing FROM-clause entry for table "LIBN02"
SQL state: 42P01
Context: PL/pgSQL function trigger_test_1_soft_delete() line 5 at EXECUTE

我应该改变什么才能使它起作用？

Answer 1

您收到的错误是因为"LIBN02"."trigger_test_1" 不是 字符串（用单引号括起来），而是一个标识符。你应该使用

EXECUTE 'UPDATE "' || TG_TABLE_SCHEMA || '"."' || TG_TABLE_NAME || '" ' || command
   USING OLD.uuid_col;

您还可以将AND NOT deleted 添加到WHERE 子句以避免不必要的流失。