Mysql Constraint problem
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by Bramjam
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Published on 2010-05-11T11:18:57Z
Indexed on
2010/05/11
11:24 UTC
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Hit count: 114
mysql
this is my table
/* oefenreeks leerplan */
CREATE TABLE leerplan_oefenreeks
(
leerplan_oefenreeks_id INT PRIMARY KEY AUTO_INCREMENT NOT NULL,
leerplan_id INT NOT NULL,
oefenreeks_id INT NOT NULL,
plaats INT NOT NULL
);
/* fk */
ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT fk_leerp_oefenr_leerplan FOREIGN KEY(leerplan_id) REFERENCES leerplan (leerplan_id) ON DELETE CASCADE;
ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT fk_leerp_oefenr_oefenreeks FOREIGN KEY(oefenreeks_id) REFERENCES oefenreeks (oefenreeks_id) ON DELETE CASCADE;
/* unique s */
/*when I execute the nexline, my fk_leerp_oefenr_leerplan constraint vanishes/disappears*/
ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT un_leerp_oefenr UNIQUE(leerplan_id, oefenreeks_id);ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT un_leerp_oefenr_plaats UNIQUE(leerplan_id, plaats);
when I go and check only 3 constraints exist (fk_leerp_oefenr_leerplan is gone)
I don't understand why this happens, plz tell me (if you need more info just ask ;)
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