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119 lines
2.3 KiB
119 lines
2.3 KiB
CREATE EXTENSION lo;
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CREATE TABLE image (title text, raster lo);
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CREATE TRIGGER t_raster BEFORE UPDATE OR DELETE ON image
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FOR EACH ROW EXECUTE PROCEDURE lo_manage(raster);
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SELECT lo_create(43213);
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lo_create
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-----------
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43213
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(1 row)
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SELECT lo_create(43214);
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lo_create
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-----------
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43214
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(1 row)
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INSERT INTO image (title, raster) VALUES ('beautiful image', 43213);
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SELECT lo_get(43213);
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lo_get
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--------
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\x
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(1 row)
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SELECT lo_get(43214);
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lo_get
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--------
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\x
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(1 row)
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UPDATE image SET raster = 43214 WHERE title = 'beautiful image';
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SELECT lo_get(43213);
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ERROR: large object 43213 does not exist
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SELECT lo_get(43214);
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lo_get
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--------
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\x
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(1 row)
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-- test updating of unrelated column
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UPDATE image SET title = 'beautiful picture' WHERE title = 'beautiful image';
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SELECT lo_get(43214);
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lo_get
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--------
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\x
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(1 row)
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DELETE FROM image;
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SELECT lo_get(43214);
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ERROR: large object 43214 does not exist
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-- Now let's try it with an AFTER trigger
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DROP TRIGGER t_raster ON image;
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CREATE CONSTRAINT TRIGGER t_raster AFTER UPDATE OR DELETE ON image
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DEFERRABLE INITIALLY DEFERRED
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FOR EACH ROW EXECUTE PROCEDURE lo_manage(raster);
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SELECT lo_create(43223);
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lo_create
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-----------
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43223
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(1 row)
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SELECT lo_create(43224);
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lo_create
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-----------
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43224
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(1 row)
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SELECT lo_create(43225);
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lo_create
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-----------
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43225
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(1 row)
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INSERT INTO image (title, raster) VALUES ('beautiful image', 43223);
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SELECT lo_get(43223);
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lo_get
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--------
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\x
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(1 row)
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UPDATE image SET raster = 43224 WHERE title = 'beautiful image';
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SELECT lo_get(43223); -- gone
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ERROR: large object 43223 does not exist
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SELECT lo_get(43224);
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lo_get
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--------
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\x
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(1 row)
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-- test updating of unrelated column
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UPDATE image SET title = 'beautiful picture' WHERE title = 'beautiful image';
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SELECT lo_get(43224);
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lo_get
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--------
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\x
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(1 row)
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-- this case used to be buggy
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BEGIN;
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UPDATE image SET title = 'beautiful image' WHERE title = 'beautiful picture';
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UPDATE image SET raster = 43225 WHERE title = 'beautiful image';
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SELECT lo_get(43224);
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lo_get
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--------
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\x
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(1 row)
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COMMIT;
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SELECT lo_get(43224); -- gone
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ERROR: large object 43224 does not exist
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SELECT lo_get(43225);
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lo_get
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--------
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\x
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(1 row)
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DELETE FROM image;
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SELECT lo_get(43225); -- gone
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ERROR: large object 43225 does not exist
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DROP TABLE image;
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