34 lines
1.2 KiB
MySQL
34 lines
1.2 KiB
MySQL
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-- AlterTable
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ALTER TABLE "Item" ADD COLUMN "weightedVotes" DOUBLE PRECISION NOT NULL DEFAULT 0;
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-- loop over all existing votes and denormalize them
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UPDATE "Item"
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SET "weightedVotes" = subquery.votes
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FROM (SELECT "ItemAct"."itemId", SUM(users.trust) AS votes
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FROM "ItemAct"
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JOIN users ON "ItemAct"."userId" = users.id
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JOIN "Item" ON "Item".id = "ItemAct"."itemId"
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WHERE "ItemAct".act = 'VOTE' AND "Item"."userId" <> "ItemAct"."userId"
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GROUP BY "ItemAct"."itemId") subquery
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WHERE "Item".id = subquery."itemId";
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CREATE OR REPLACE FUNCTION weighted_votes_after_act() RETURNS TRIGGER AS $$
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DECLARE
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user_trust DOUBLE PRECISION;
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BEGIN
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-- grab user's trust who is upvoting
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SELECT trust INTO user_trust FROM users WHERE id = NEW."userId";
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-- update item
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UPDATE "Item"
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SET "weightedVotes" = "weightedVotes" + user_trust
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WHERE id = NEW."itemId" AND "userId" <> NEW."userId";
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RETURN NEW;
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END;
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$$ LANGUAGE plpgsql;
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DROP TRIGGER IF EXISTS weighted_votes_after_act ON "ItemAct";
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CREATE TRIGGER weighted_votes_after_act
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AFTER INSERT ON "ItemAct"
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FOR EACH ROW
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WHEN (NEW.act = 'VOTE')
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EXECUTE PROCEDURE weighted_votes_after_act();
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