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27 lines
727 B
Text
27 lines
727 B
Text
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CREATE TABLE parent (
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id INT PRIMARY KEY,
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KEY (id)
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) ENGINE=InnoDB;
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CREATE TABLE child (
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id INT PRIMARY KEY,
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parent_id INT,
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FOREIGN KEY (parent_id)
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REFERENCES parent(id)
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) ENGINE=InnoDB;
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INSERT INTO parent VALUES (1);
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INSERT INTO child VALUES (1,1);
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SET SESSION foreign_key_checks = 0;
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INSERT INTO child VALUES (2,2);
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SELECT COUNT(*) = 1 FROM child WHERE id = 2;
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COUNT(*) = 1
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1
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INSERT INTO child VALUES (3,3);
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ERROR 23000: Cannot add or update a child row: a foreign key constraint fails (`test`.`child`, CONSTRAINT `child_ibfk_1` FOREIGN KEY (`parent_id`) REFERENCES `parent` (`id`))
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SET SESSION foreign_key_checks = 0;
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DELETE FROM parent;
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SELECT COUNT(*) = 0 FROM parent;
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COUNT(*) = 0
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1
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DROP TABLE child;
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DROP TABLE parent;
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