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-- https://wiki.postgresql.org/wiki/Count_estimate
INSERT INTO GlobalIntegers
SELECT 2, CAST(COALESCE(COUNT(*), 0) AS BIGINT) FROM Resources WHERE resourceType = 0; -- Count patients
INSERT INTO GlobalIntegers
SELECT 3, CAST(COALESCE(COUNT(*), 0) AS BIGINT) FROM Resources WHERE resourceType = 1; -- Count studies
INSERT INTO GlobalIntegers
SELECT 4, CAST(COALESCE(COUNT(*), 0) AS BIGINT) FROM Resources WHERE resourceType = 2; -- Count series
INSERT INTO GlobalIntegers
SELECT 5, CAST(COALESCE(COUNT(*), 0) AS BIGINT) FROM Resources WHERE resourceType = 3; -- Count instances
CREATE OR REPLACE FUNCTION CountResourcesTrackerFunc()
RETURNS TRIGGER AS $$
BEGIN
IF TG_OP = 'INSERT' THEN
UPDATE GlobalIntegers SET value = value + 1 WHERE key = new.resourceType + 2;
RETURN new;
ELSIF TG_OP = 'DELETE' THEN
UPDATE GlobalIntegers SET value = value - 1 WHERE key = old.resourceType + 2;
RETURN old;
END IF;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER CountResourcesTracker
AFTER INSERT OR DELETE ON Resources
FOR EACH ROW
EXECUTE PROCEDURE CountResourcesTrackerFunc();
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