81 lines
2.5 KiB
Plaintext
81 lines
2.5 KiB
Plaintext
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;; Postgresql C library interface, example program 1, using the xedit
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;; lisp interface
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;; Test the C version of libpq, the PostgreSQL frontend library.
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(require "psql")
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(defun exit-nicely (conn)
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(pq-finish conn)
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(quit 1)
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)
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;; begin, by setting the parameters for a backend connection if the
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;; parameters are null, then the system will try to use reasonable
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;; defaults by looking up environment variables or, failing that,
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;; using hardwired constants
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(setq pghost nil) ; host name of the backend server
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(setq pgport nil) ; port of the backend server
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(setq pgoptions nil) ; special options to start up the backend server
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(setq pgtty nil) ; debugging tty for the backend server
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(setq pgdbname "template1")
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;; make a connection to the database
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(setq conn (pq-setdb pghost pgport pgoptions pgtty pgdbname))
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;; check to see that the backend connection was successfully made
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(when (= (pq-status conn) pg-connection-bad)
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(format t "Connection to database '~A' failed.~%" pgdbname)
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(format t "~A" (pq-error-message conn))
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(exit-nicely conn))
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;; start a transaction block
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(setq res (pq-exec conn "BEGIN"))
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(when (or (null res) (not (= (pq-result-status res) pgres-command-ok)))
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(format t "BEGIN command failed~%")
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(pq-clear res)
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(exit-nicely conn))
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;; Should PQclear PGresult whenever it is no longer needed to avoid memory leaks
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(pq-clear res)
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;; fetch rows from the pg_database, the system catalog of databases
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(setq res (pq-exec conn "DECLARE mycursor CURSOR FOR select * from pg_database"))
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(when (or (null res) (not (= (pq-result-status res) pgres-command-ok)))
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(format t "DECLARE CURSOR command failed~%")
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(pq-clear res)
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(exit-nicely conn))
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(pq-clear res)
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(setq res (pq-exec conn "FETCH ALL in mycursor"))
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(when (or (null res) (not (= (pq-result-status res) pgres-tuples-ok)))
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(format t "FETCH ALL command didn't return tuples properly~%")
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(pq-clear res)
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(exit-nicely conn))
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;; first, print out the attribute names
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(setq nfields (pq-nfields res))
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(dotimes (i nfields)
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(format t "~15@<~A~>" (pq-fname res i))
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)
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(format t "~%")
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;; next, print out the rows
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(setq ntuples (pq-ntuples res))
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(dotimes (i ntuples)
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(dotimes (j nfields)
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(format t "~15@<~A~>" (pq-getvalue res i j))
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)
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(format t "~%")
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)
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(pq-clear res)
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;; close the cursor
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(setq res (pq-exec conn "CLOSE mycursor"))
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(pq-clear res)
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;; commit the transaction
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(setq res (pq-exec conn "COMMIT"))
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(pq-clear res)
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;; close the connection to the database and cleanup
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(pq-finish conn)
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