How to avoid circular Trigger dependencies in MySQL

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北恋

I have a little probleme using Triggers in MySQL.

Suppose we have 2 tables:

TableA
TableB

And 2 Triggers:

Trigger

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花落未央

2020-12-09 14:33

Try to use variable.

First trigger:

CREATE TRIGGER trigger1
  BEFORE DELETE
  ON table1
  FOR EACH ROW
BEGIN
  IF @deleting IS NULL THEN
    SET @deleting = 1;
    DELETE FROM table2 WHERE id = OLD.id;
    SET @deleting = NULL;
  END IF;
END

Second trigger:

CREATE TRIGGER trigger2
  BEFORE DELETE
  ON table2
  FOR EACH ROW
BEGIN
  IF @deleting IS NULL THEN
    SET @deleting = 1;
    DELETE FROM table1 WHERE id = OLD.id;
    SET @deleting = NULL;
  END IF;
END

And additional AFTER DELETE triggers:

CREATE TRIGGER trigger3
  AFTER DELETE
  ON table1
  FOR EACH ROW
BEGIN
  SET @deleting = NULL;
END

CREATE TRIGGER trigger4
  AFTER DELETE
  ON table2
  FOR EACH ROW
BEGIN
  SET @deleting = NULL;
END

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