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45 lines
1.0 KiB
Python
45 lines
1.0 KiB
Python
import psycopg2
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import traceback
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# Change the table here to something the user can create tables in ...
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db = psycopg2.connect('dbname=test')
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cursor = db.cursor()
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print('Creating tables and sample data')
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cursor.execute('''
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CREATE TEMPORARY TABLE foo (
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id int PRIMARY KEY
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)''')
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cursor.execute('''
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CREATE TEMPORARY TABLE bar (
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id int PRIMARY KEY,
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foo_id int,
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CONSTRAINT bar_foo_fk FOREIGN KEY (foo_id) REFERENCES foo(id) DEFERRABLE
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)''')
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cursor.execute('INSERT INTO foo VALUES (1)')
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cursor.execute('INSERT INTO bar VALUES (1, 1)')
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db.commit()
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print('Deferring constraint and breaking referential integrity')
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cursor.execute('SET CONSTRAINTS bar_foo_fk DEFERRED')
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cursor.execute('UPDATE bar SET foo_id = 42 WHERE id = 1')
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print('Committing (this should fail)')
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try:
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db.commit()
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except:
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traceback.print_exc()
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print('Rolling back connection')
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db.rollback()
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print('Running a trivial query')
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try:
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cursor.execute('SELECT TRUE')
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except:
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traceback.print_exc()
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print('db.closed:', db.closed)
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