@ -1,6 +1,6 @@
#------------------------------------------------------- #-------------------------------------------------------
# #
# $Id: Pg.pm,v 1.7 1998/06/01 16:41:19 mergl Exp $ # $Id: Pg.pm,v 1.8 1998/09/27 19:12:22 mergl Exp $
# #
# Copyright (c) 1997, 1998 Edmund Mergl # Copyright (c) 1997, 1998 Edmund Mergl
# #
@ -22,32 +22,46 @@ require 5.002;
# Items to export into callers namespace by default. # Items to export into callers namespace by default.
@ EXPORT = qw( @ EXPORT = qw(
PQconnectdb PQconnectdb
PQconndefaults PQsetdbLogin
PQsetdb PQsetdb
PQconndefaults
PQfinish PQfinish
PQreset PQreset
PQrequestCancel
PQdb PQdb
PQuser PQuser
PQpass
PQhost PQhost
PQoptions
PQport PQport
PQtty PQtty
PQoptions
PQstatus PQstatus
PQerrorMessage PQerrorMessage
PQsocket
PQbackendPID
PQtrace PQtrace
PQuntrace PQuntrace
PQexec PQexec
PQnotifies
PQsendQuery
PQgetResult
PQisBusy
PQconsumeInput
PQgetline PQgetline
PQendcopy
PQputline PQputline
PQnotifies PQgetlineAsync
PQputnbytes
PQendcopy
PQmakeEmptyPGresult
PQresultStatus PQresultStatus
PQntuples PQntuples
PQnfields PQnfields
PQbinaryTuples
PQfname PQfname
PQfnumber PQfnumber
PQftype PQftype
PQfsize PQfsize
PQfmod
PQcmdStatus PQcmdStatus
PQoidStatus PQoidStatus
PQcmdTuples PQcmdTuples
@ -55,8 +69,9 @@ require 5.002;
PQgetlength PQgetlength
PQgetisnull PQgetisnull
PQclear PQclear
PQprintTuples
PQprint PQprint
PQdisplayTuples
PQprintTuples
PQlo_open PQlo_open
PQlo_close PQlo_close
PQlo_read PQlo_read
@ -84,7 +99,7 @@ require 5.002;
PGRES_InvalidOid PGRES_InvalidOid
) ; ) ;
$ Pg:: VERSION = '1.7.4 ' ; $ Pg:: VERSION = '1.8.0 ' ;
sub AUTOLOAD { sub AUTOLOAD {
# This AUTOLOAD is used to 'autoload' constants from the constant() # This AUTOLOAD is used to 'autoload' constants from the constant()
@ -145,15 +160,15 @@ Pg - Perl5 extension for PostgreSQL
new style: new style:
use Pg ; use Pg ;
$ conn = Pg:: connectdb ( "dbname = template1" ) ; $ conn = Pg:: connectdb ( "dbname=template1" ) ;
$ result = $ conn - > exec ( "create database test" ) ; $ result = $ conn - > exec ( "create database pg test" ) ;
you may also use the old style :old style ( depreciated ) :
use Pg ; use Pg ;
$ conn = PQsetdb ( '' , '' , '' , '' , template1 ) ; $ conn = PQsetdb ( '' , '' , '' , '' , template1 ) ;
$ result = PQexec ( $ conn , "create database test" ) ; $ result = PQexec ( $ conn , "create database pg test" ) ;
PQclear ( $ result ) ; PQclear ( $ result ) ;
PQfinish ( $ conn ) ; PQfinish ( $ conn ) ;
@ -232,41 +247,58 @@ implemented in perl using lists or hash.
= head1 FUNCTIONS = head1 FUNCTIONS
The functions have been divided into three sections: The functions have been divided into three sections:
Connection , Result , Large Objects . Connection , Result , Large Objects . For details please
read L <libpq> .
= head2 1 . Connection = head2 1 . Connection
With these functions you can establish and close a connection to a With these functions you can establish and close a connection to a
database . In Libpq a connection is represented by a structure called database . In Libpq a connection is represented by a structure called
PGconn . Using the appropriate methods you can access almost all PGconn .
fields of this structure .
When opening a connection a given database name is always converted to
lower - case , unless it is surrounded by double quotes . All unspecified
parameters are replaced by environment variables or by hard coded defaults:
parameter environment variable hard coded default
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
host PGHOST localhost
port PGPORT 5432
options PGOPTIONS ""
tty PGTTY ""
dbname PGDATABASE current userid
user PGUSER current userid
password PGPASSWORD ""
Using appropriate methods you can access almost all fields of the
returned PGconn structure .
$ conn = Pg:: setdbLogin ( $ pghost , $ pgport , $ pgoptions , $ pgtty , $ dbname , $ login , $ pwd )
Opens a new connection to the backend . The connection identifier $ conn
( a pointer to the PGconn structure ) must be used in subsequent commands
for unique identification . Before using $ conn you should call $ conn - > status
to ensure , that the connection was properly made .
$ conn = Pg:: setdb ( $ pghost , $ pgport , $ pgoptions , $ pgtty , $ dbname ) $ conn = Pg:: setdb ( $ pghost , $ pgport , $ pgoptions , $ pgtty , $ dbname )
Opens a new connection to the backend . You may use an empty string for The method setdb should be used when username / password authentication is
any argument , in which case first the environment is checked and then not needed .
hard - coded defaults are used . The connection identifier $ conn ( a pointer
to the PGconn structure ) must be used in subsequent commands for unique
identification . Before using $ conn you should call $ conn - > status to ensure ,
that the connection was properly made . Use the methods below to access
the contents of the PGconn structure .
$ conn = Pg:: connectdb ( "option1=value option2=value ..." ) $ conn = Pg:: connectdb ( "option1=value option2=value ..." )
Opens a new connection to the backend using connection information in a string . Opens a new connection to the backend using connection information in a
Possible options are: dbname , host , user , password , authtype , port , tty , options . string . Possible options are: host , port , options , tty , dbname , user , password .
The database - name will be converted to lower - case , unless it is surrounded by The connection identifier $ conn ( a pointer to the PGconn structure )
double quotes . The connection identifier $ conn ( a pointer to the PGconn structure ) must be used in subsequent commands for unique identification . Before using
must be used in subsequent commands for unique identification . Before using $ conn $ conn you should call $ conn - > status to ensure , that the connection was
you should call $ conn - > status to ensure , that the connection was properly made . properly made .
Use the methods below to access the contents of the PGconn structure .
$ Option_ref = Pg:: conndefaults ( ) $ Option_ref = Pg:: conndefaults ( )
while ( ( $ key , $ val ) = each %$ Option_ref ) { while ( ( $ key , $ val ) = each %$ Option_ref ) {
print "$key, $val\n" ; print "$key, $val\n" ;
}
Returns a reference to a hash containing as keys all possible options for Returns a reference to a hash containing as keys all possible options for
connectdb ( ) . The values are the current defaults . This function differs from connectdb ( ) . The values are the current defaults . This function differs from
@ -275,13 +307,20 @@ his C-counterpart, which returns the complete conninfoOption structure.
PQfinish ( $ conn ) PQfinish ( $ conn )
Old style only ! Old style only !
Closes the connection to the backend and frees all memory . Closes the connection to the backend and frees the connection data structure .
$ conn - > reset $ conn - > reset
Resets the communication port with the backend and tries Resets the communication port with the backend and tries
to establish a new connection . to establish a new connection .
$ ret = $ conn - > requestCancel
Abandon processing of the current query . Regardless of the return value of
requestCancel , the application must continue with the normal result - reading
sequence using getResult . If the current query is part of a transaction ,
cancellation will abort the whole transaction .
$ dbname = $ conn - > db $ dbname = $ conn - > db
Returns the database name of the connection . Returns the database name of the connection .
@ -290,13 +329,13 @@ Returns the database name of the connection.
Returns the Postgres user name of the connection . Returns the Postgres user name of the connection .
$ pghost = $ conn - > host $ pguser = $ conn - > pass
Returns the host name of the connection . Returns the Postgres password of the connection .
$ pgoptions = $ conn - > options $ pghost = $ conn - > host
Returns the options used in the connection . Returns the host name of the connection .
$ pgport = $ conn - > port $ pgport = $ conn - > port
@ -306,6 +345,10 @@ Returns the port of the connection.
Returns the tty of the connection . Returns the tty of the connection .
$ pgoptions = $ conn - > options
Returns the options used in the connection .
$ status = $ conn - > status $ status = $ conn - > status
Returns the status of the connection . For comparing the status Returns the status of the connection . For comparing the status
@ -318,6 +361,15 @@ you may use the following constants:
Returns the last error message associated with this connection . Returns the last error message associated with this connection .
$ fd = $ conn - > socket
Obtain the file descriptor number for the backend connection socket .
A result of - 1 indicates that no backend connection is currently open .
$ pid = $ conn - > backendPID
Returns the process - id of the corresponding backend proceess .
$ conn - > trace ( debug_port ) $ conn - > trace ( debug_port )
Messages passed between frontend and backend are echoed to the Messages passed between frontend and backend are echoed to the
@ -338,6 +390,39 @@ structure has to be freed using PQfree. Before using $result you
should call resultStatus to ensure , that the query was should call resultStatus to ensure , that the query was
properly executed . properly executed .
( $ table , $ pid ) = $ conn - > notifies
Checks for asynchronous notifications . This functions differs from
the C - counterpart which returns a pointer to a new allocated structure ,
whereas the perl implementation returns a list . $ table is the table
which has been listened to and $ pid is the process id of the backend .
$ ret = $ conn - > sendQuery ( $ string , $ query )
Submit a query to Postgres without waiting for the result ( s ) . After
successfully calling PQsendQuery , call PQgetResult one or more times
to obtain the query results . PQsendQuery may not be called again until
getResult has returned NULL , indicating that the query is done .
$ result = $ conn - > getResult
Wait for the next result from a prior PQsendQuery , and return it . NULL
is returned when the query is complete and there will be no more results .
getResult will block only if a query is active and the necessary response
data has not yet been read by PQconsumeInput .
$ ret = $ conn - > isBusy
Returns TRUE if a query is busy , that is , PQgetResult would block waiting
for input . A FALSE return indicates that PQgetResult can be called with
assurance of not blocking .
$ result = $ conn - > consumeInput
If input is available from the backend , consume it . After calling consumeInput ,
the application may check isBusy and / or notifies to see if their state has changed .
$ ret = $ conn - > getline ( $ string , $ length ) $ ret = $ conn - > getline ( $ string , $ length )
Reads a string up to $ length - 1 characters from the backend . Reads a string up to $ length - 1 characters from the backend .
@ -346,26 +431,34 @@ and 1 if the buffer is full. If a line consists of the two
characters "\." the backend has finished sending the results of characters "\." the backend has finished sending the results of
the copy command . the copy command .
$ conn - > putline ( $ string ) $ ret = $ conn - > putline ( $ string )
Sends a string to the backend . The application must explicitly Sends a string to the backend . The application must explicitly
send the two characters "\." to indicate to the backend that send the two characters "\." to indicate to the backend that
it has finished sending its data . it has finished sending its data .
$ ret = $ conn - > getlineAsync ( $ buffer , $ bufsize )
Non - blocking version of getline . It reads up to $ bufsize
characters from the backend . getlineAsync returns - 1 if
the end - of - copy - marker has been recognized , 0 if no data
is avilable , and > 0 the number of bytes returned .
$ ret = $ conn - > putnbytes ( $ buffer , $ nbytes )
Sends n bytes to the backend . Returns 0 if OK , EOF if not .
$ ret = $ conn - > endcopy $ ret = $ conn - > endcopy
This function waits until the backend has finished the copy . This function waits until the backend has finished the copy .
It should either be issued when the last string has been sent It should either be issued when the last string has been sent
to the backend using putline or when the last string has to the backend using putline or when the last string has
been received from the backend using getline . endcopy returns been received from the backend using getline . endcopy returns
0 on success , nonzero otherwise . 0 on success , 1 on failur e.
( $ table , $ pid ) = $ conn - > notifies $ result = $ conn - > makeEmptyPGresult ( $ status ) ;
Checks for asynchronous notifications . This functions differs from Returns a newly allocated , initialized result with given status .
the C - counterpart which returns a pointer to a new allocated structure ,
whereas the perl implementation returns a list . $ table is the table
which has been listened to and $ pid is the process id of the backend .
= head2 2 . Result = head2 2 . Result
@ -375,6 +468,21 @@ investigate the results. In Libpq the result of a command is
represented by a structure called PGresult . Using the appropriate represented by a structure called PGresult . Using the appropriate
methods you can access almost all fields of this structure . methods you can access almost all fields of this structure .
$ result_status = $ result - > resultStatus
Returns the status of the result . For comparing the status you
may use one of the following constants depending upon the
command executed:
- PGRES_EMPTY_QUERY
- PGRES_COMMAND_OK
- PGRES_TUPLES_OK
- PGRES_COPY_OUT
- PGRES_COPY_IN
- PGRES_BAD_RESPONSE
- PGRES_NONFATAL_ERROR
- PGRES_FATAL_ERROR
Use the functions below to access the contents of the PGresult structure . Use the functions below to access the contents of the PGresult structure .
$ ntuples = $ result - > ntuples $ ntuples = $ result - > ntuples
@ -385,6 +493,10 @@ Returns the number of tuples in the query result.
Returns the number of fields in the query result . Returns the number of fields in the query result .
$ ret = $ result - > binaryTuples
Returns 1 if the tuples in the query result are bianry .
$ fname = $ result - > fname ( $ field_num ) $ fname = $ result - > fname ( $ field_num )
Returns the field name associated with the given field number . Returns the field name associated with the given field number .
@ -402,34 +514,10 @@ Returns the oid of the type of the given field number.
Returns the size in bytes of the type of the given field number . Returns the size in bytes of the type of the given field number .
It returns - 1 if the field has a variable length . It returns - 1 if the field has a variable length .
$ value = $ result - > getvalue ( $ tup_num , $ field_num ) $ fmod = $ result - > fmod ( $ field_num )
Returns the value of the given tuple and field . This is
a null - terminated ASCII string . Binary cursors will not
work .
$ length = $ result - > getlength ( $ tup_num , $ field_num )
Returns the length of the value for a given tuple and field .
$ null_status = $ result - > getisnull ( $ tup_num , $ field_num )
Returns the NULL status for a given tuple and field .
$ result_status = $ result - > resultStatus Returns the type - specific modification data of the field associated
with the given field index . Field indices start at 0 .
Returns the status of the result . For comparing the status you
may use one of the following constants depending upon the
command executed:
- PGRES_EMPTY_QUERY
- PGRES_COMMAND_OK
- PGRES_TUPLES_OK
- PGRES_COPY_OUT
- PGRES_COPY_IN
- PGRES_BAD_RESPONSE
- PGRES_NONFATAL_ERROR
- PGRES_FATAL_ERROR
$ cmdStatus = $ result - > cmdStatus $ cmdStatus = $ result - > cmdStatus
@ -449,9 +537,30 @@ inserted tuple.
In case the last query was an INSERT or DELETE command it returns the In case the last query was an INSERT or DELETE command it returns the
number of affected tuples . number of affected tuples .
$ result - > printTuples ( $ fout , $ printAttName , $ terseOutput , $ width ) $ value = $ result - > getvalue ( $ tup_num , $ field_num )
Kept for backward compatibility . Use print . Returns the value of the given tuple and field . This is
a null - terminated ASCII string . Binary cursors will not
work .
$ length = $ result - > getlength ( $ tup_num , $ field_num )
Returns the length of the value for a given tuple and field .
$ null_status = $ result - > getisnull ( $ tup_num , $ field_num )
Returns the NULL status for a given tuple and field .
PQclear ( $ result )
Old style only !
Frees all memory of the given result .
$ res - > fetchrow
New style only !
Fetches the next row from the server and returns NULL if all rows
have been processed . Columns which have NULL as value will be set to C <undef> .
$ result - > print ( $ fout , $ header , $ align , $ standard , $ html3 , $ expanded , $ pager , $ fieldSep , $ tableOpt , $ caption , ... ) $ result - > print ( $ fout , $ header , $ align , $ standard , $ html3 , $ expanded , $ pager , $ fieldSep , $ tableOpt , $ caption , ... )
@ -464,10 +573,13 @@ are boolean flags. The arguments $fieldSep, $tableOpt, $caption
are strings . You may append additional strings , which will be are strings . You may append additional strings , which will be
taken as replacement for the field names . taken as replacement for the field names .
PQclear ( $ resul t) $ result - > displayTuples ( $ fp , $ fillAlign , $ fieldSep , $ printHeader , qie t)
Old style only ! Kept for backward compatibility . Use print .
Frees all memory of the given result .
$ result - > printTuples ( $ fout , $ printAttName , $ terseOutput , $ width )
Kept for backward compatibility . Use print .
= head2 3 . Large Objects = head2 3 . Large Objects
@ -478,22 +590,6 @@ system interface with analogies of open, close, read, write,
lseek , tell . In order to get a consistent naming , all function lseek , tell . In order to get a consistent naming , all function
names have been prepended with 'PQ' ( old style only ) . names have been prepended with 'PQ' ( old style only ) .
$ lobjId = $ conn - > lo_creat ( $ mode )
Creates a new large object . $ mode is a bit - mask describing
different attributes of the new object . Use the following constants:
- PGRES_INV_SMGRMASK
- PGRES_INV_ARCHIVE
- PGRES_INV_WRITE
- PGRES_INV_READ
Upon failure it returns PGRES_InvalidOid .
$ ret = $ conn - > lo_unlink ( $ lobjId )
Deletes a large object . Returns - 1 upon failure .
$ lobj_fd = $ conn - > lo_open ( $ lobjId , $ mode ) $ lobj_fd = $ conn - > lo_open ( $ lobjId , $ mode )
Opens an existing large object and returns an object id . Opens an existing large object and returns an object id .
@ -519,11 +615,27 @@ Returns the number of bytes written and -1 upon failure.
Change the current read or write location on the large object Change the current read or write location on the large object
$ obj_id . Currently $ whence can only be 0 ( L_SET ) . $ obj_id . Currently $ whence can only be 0 ( L_SET ) .
$ lobjId = $ conn - > lo_creat ( $ mode )
Creates a new large object . $ mode is a bit - mask describing
different attributes of the new object . Use the following constants:
- PGRES_INV_SMGRMASK
- PGRES_INV_ARCHIVE
- PGRES_INV_WRITE
- PGRES_INV_READ
Upon failure it returns PGRES_InvalidOid .
$ location = $ conn - > lo_tell ( $ lobj_fd ) $ location = $ conn - > lo_tell ( $ lobj_fd )
Returns the current read or write location on the large object Returns the current read or write location on the large object
$ lobj_fd . $ lobj_fd .
$ ret = $ conn - > lo_unlink ( $ lobjId )
Deletes a large object . Returns - 1 upon failure .
$ lobjId = $ conn - > lo_import ( $ filename ) $ lobjId = $ conn - > lo_import ( $ filename )
Imports a Unix file as large object and returns Imports a Unix file as large object and returns
Edmund Mergl
27 years ago