67 lines
2.0 KiB
MySQL
67 lines
2.0 KiB
MySQL
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CREATE TRIGGER balanceTransfer
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AFTER INSERT ON Transfer
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BEGIN
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SELECT RAISE(FAIL, "It is not the debtor who is set to pay")
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WHERE (SELECT debtor FROM Debit WHERE billId=NEW.billId)
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!= (SELECT account FROM Credit WHERE credId=NEW.credId)
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;
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SELECT RAISE(FAIL, "Target of a debit cannot be an incoming payment")
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FROM Credit c
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JOIN Debit d ON c.credId = d.targetCredit
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WHERE c.credId = NEW.credId
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AND c.value > 0
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GROUP BY c.credId
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HAVING count(d.billId) == 0
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;
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INSERT INTO __DO_NOT_MANIPULATE__trigger_memory
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SELECT remainingDebt, remainingCredit, min(remainingDebt,remainingCredit)
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FROM (SELECT
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(SELECT value - paid FROM Debit WHERE billId=NEW.billId) AS remainingDebt,
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(SELECT value - spent FROM Credit WHERE credId=NEW.credId) AS remainingCredit
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)
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;
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UPDATE Debit
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SET paid = paid + CASE
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WHEN (SELECT d FROM __DO_NOT_MANIPULATE__trigger_memory) <= 0
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THEN RAISE(FAIL, "Debt settled")
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ELSE
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(SELECT m FROM __DO_NOT_MANIPULATE__trigger_memory)
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END
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WHERE billId=NEW.billId;
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UPDATE Credit
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SET spent = spent + CASE
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WHEN (SELECT c FROM __DO_NOT_MANIPULATE__trigger_memory) <= 0
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THEN RAISE(FAIL, "Credit spent")
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ELSE IFNULL(
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(SELECT m FROM __DO_NOT_MANIPULATE__trigger_memory),
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RAISE(FAIL,"Oops, lost __DO_NOT_MANIPULATE__trigger_memory record before increasing spent")
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)
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END
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WHERE credId=NEW.credId;
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UPDATE Transfer
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SET amount = (SELECT m FROM __DO_NOT_MANIPULATE__trigger_memory)
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WHERE billId=NEW.billId AND credId=NEW.credId
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;
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UPDATE Credit
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SET value = value + IFNULL(
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(SELECT m FROM __DO_NOT_MANIPULATE__trigger_memory),
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RAISE(FAIL, "Oops, lost __DO_NOT_MANIPULATE__trigger_memory record before increasing value")
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)
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WHERE credId = (
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SELECT targetCredit
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FROM Debit
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WHERE billId=NEW.billId
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);
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DELETE FROM __DO_NOT_MANIPULATE__trigger_memory;
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END;
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