PostgreSQL Postgres, developed originally in the UC Berkeley Computer Science Department, pioneered many of the object-relational concepts now becoming available in some commercial databases. It provides SQL92/SQL3 language support, transaction integrity, and type extensibility. PostgreSQL is a public-domain, open source descendant of this original Berkeley code. PostgreSQL is available without cost. The current version is available at www.PostgreSQL.org. Since version 6.3 (03/02/1998) PostgreSQL uses unix domain sockets. A table is shown below describing these new connection possibilities. This socket will be found in /tmp/.s.PGSQL.5432. This option can be enabled with the '-i' flag to postmaster and it's meaning is: "listen on TCP/IP sockets as well as Unix domain sockets". Postmaster PHP Status postmaster & pg_connect("dbname=MyDbName"); OK postmaster -i & pg_connect("dbname=MyDbName"); OK postmaster & pg_connect("host=localhost dbname=MyDbName"); Unable to connect to PostgreSQL server: connectDB() failed: Is the postmaster running and accepting TCP/IP (with -i) connection at 'localhost' on port '5432'? in /path/to/file.php3 on line 20. postmaster -i & pg_connect("host=localhost dbname=MyDbName"); OK One can establish a connection with the following value pairs set in the command string: $conn = pg_Connect("host=myHost port=myPort tty=myTTY options=myOptions user=myUser password=myPassword dbname=myDB"); The previous syntax of: $conn = pg_connect ("host", "port", "options", "tty", "dbname") has been deprecated. To use the large object (lo) interface, it is necessary to enclose it within a transaction block. A transaction block starts with a begin and if the transaction was valid ends with commit or end. If the transaction fails the transaction should be closed with rollback or abort. <?php $database = pg_Connect ("dbname=jacarta"); pg_exec ($database, "begin"); $oid = pg_locreate ($database); echo ("$oid\n"); $handle = pg_loopen ($database, $oid, "w"); echo ("$handle\n"); pg_lowrite ($handle, "gaga"); pg_loclose ($handle); pg_exec ($database, "commit"); ?> pg_close Close a PostgreSQL connection bool pg_close int connection Returns false if connection is not a valid connection index, true otherwise. Closes down the connection to a PostgreSQL database associated with the given connection index. This isn't usually necessary, as non-persistent open links are automatically closed at the end of the script's execution. pg_close will not close persistent links generated by pg_pconnect. pg_cmdtuples Returns number of affected tuples int pg_cmdtuples int result_id Pg_cmdtuples returns the number of tuples (instances) affected by INSERT, UPDATE, and DELETE queries. If no tuple is affected the function will return 0. <?php $result = pg_exec ($conn, "INSERT INTO publisher VALUES ('Author')"); $cmdtuples = pg_cmdtuples ($result); echo $cmdtuples . " <- cmdtuples affected."; ?> pg_connect Open a PostgreSQL connection int pg_connect string conn_string Returns a connection index on success, or false if the connection could not be made. Opens a connection to a PostgreSQL database. The arguments should be within a quoted string. <?php $dbconn = pg_Connect ("dbname=mary"); //connect to a database named "mary" $dbconn2 = pg_Connect ("host=localhost port=5432 dbname=mary"); //connect to a database named "mary" on "localhost" at port "5432" $dbconn3 = pg_Connect ("user=lamb passwd=baaaa dbname=mary "); //connect to a database named "mary" with a username and password ?> The arguments available include dbname port, host, tty, options, user, and password This function returns a connection index that is needed by other PostgreSQL functions. You can have multiple connections open at once. The previous syntax of: $conn = pg_connect ("host", "port", "options", "tty", "dbname") has been deprecated. See also pg_pconnect. pg_dbname Get the database name string pg_dbname int connection Returns the name of the database that the given PostgreSQL connection index is connected to, or false if connection is not a valid connection index. pg_errormessage Get the error message string string pg_errormessage int connection Returns a string containing the error message, false on failure. Details about the error probably cannot be retrieved using the pg_errormessage function if an error occured on the last database action for which a valid connection exists, this function will return a string containing the error message generated by the backend server. pg_exec Execute a query int pg_exec int connection string query Returns a result index if query could be executed, false on failure or if connection is not a valid connection index. Details about the error can be retrieved using the pg_ErrorMessage function if connection is valid. Sends an SQL statement to the PostgreSQL database specified by the connection index. The connection must be a valid index that was returned by pg_Connect. The return value of this function is an index to be used to access the results from other PostgreSQL functions. PHP/FI returned 1 if the query was not expected to return data (inserts or updates, for example) and greater than 1 even on selects that did not return anything. No such assumption can be made in PHP. pg_fetch_array Fetch a row as an array array pg_fetch_array int result int row int result_type Returns: An array that corresponds to the fetched row, or false if there are no more rows. Pg_fetch_array is an extended version of pg_fetch_row. In addition to storing the data in the numeric indices of the result array, it also stores the data in associative indices, using the field names as keys. The third optional argument result_type in pg_fetch_array is a constant and can take the following values: PGSQL_ASSOC, PGSQL_NUM, and PGSQL_BOTH. Result_type was added in PHP 4.0. An important thing to note is that using pg_fetch_array is NOT significantly slower than using pg_fetch_row, while it provides a significant added value. For further details, see also pg_fetch_row <?php $conn = pg_pconnect ("dbname=publisher"); if (!$conn) { echo "An error occured.\n"; exit; } $result = pg_Exec ($conn, "SELECT * FROM authors"); if (!$result) { echo "An error occured.\n"; exit; } $arr = pg_fetch_array ($result, 0); echo $arr[0] . " <- array\n"; $arr = pg_fetch_array ($result, 1); echo $arr["author"] . " <- array\n"; ?> pg_fetch_object Fetch a row as an object object pg_fetch_object int result int row int result_type Returns: An object with properties that correspond to the fetched row, or false if there are no more rows. Pg_fetch_object is similar to pg_fetch_array, with one difference - an object is returned, instead of an array. Indirectly, that means that you can only access the data by the field names, and not by their offsets (numbers are illegal property names). The third optional argument result_type in pg_fetch_object is a constant and can take the following values: PGSQL_ASSOC, PGSQL_NUM, and PGSQL_BOTH. Result_type was added in PHP 4.0. Speed-wise, the function is identical to pg_fetch_array, and almost as quick as pg_fetch_row (the difference is insignificant). See also: pg_fetch_array and pg_fetch_row. <?php $database = "verlag"; $db_conn = pg_connect ("host=localhost port=5432 dbname=$database"); if (!$db_conn): ?> <H1>Failed connecting to postgres database <? echo $database ?></H1> <? exit; endif; $qu = pg_exec ($db_conn, "SELECT * FROM verlag ORDER BY autor"); $row = 0; // postgres needs a row counter other dbs might not while ($data = pg_fetch_object ($qu, $row)): echo $data->autor." ("; echo $data->jahr ."): "; echo $data->titel."<BR>"; $row++; endwhile; ?> <PRE><?php $fields[] = Array ("autor", "Author"); $fields[] = Array ("jahr", " Year"); $fields[] = Array ("titel", " Title"); $row= 0; // postgres needs a row counter other dbs might not while ($data = pg_fetch_object ($qu, $row)): echo "----------\n"; reset ($fields); while (list (,$item) = each ($fields)): echo $item[1].": ".$data->$item[0]."\n"; endwhile; $row++; endwhile; echo "----------\n"; ?> </PRE> <?php pg_freeResult ($qu); pg_close ($db_conn); ?> pg_fetch_row Get a row as an enumerated array array pg_fetch_row int result int row Returns: An array that corresponds to the fetched row, or false if there are no more rows. Pg_fetch_row fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0. See also: pg_fetch_array, pg_fetch_object, pg_result. <?php $conn = pg_pconnect ("dbname=publisher"); if (!$conn) { echo "An error occured.\n"; exit; } $result = pg_Exec ($conn, "SELECT * FROM authors"); if (!$result) { echo "An error occured.\n"; exit; } $num = pg_numrows($result); for ($i=0; $i<$num; $i++) { $r = pg_fetch_row($result, $i); for ($j=0; $j<count($r); $j++) { echo "$r[$j]&nbsp;"; } echo "<BR>"; } ?> pg_fieldisnull Test if a field is NULL int pg_fieldisnull int result_id int row mixed field Test if a field is NULL or not. Returns 0 if the field in the given row is not NULL. Returns 1 if the field in the given row is NULL. Field can be specified as number or fieldname. Row numbering starts at 0. pg_fieldname Returns the name of a field string pg_fieldname int result_id int field_number Pg_fieldname will return the name of the field occupying the given column number in the given PostgreSQL result identifier. Field numbering starts from 0. pg_fieldnum Returns the field number of the named field int pg_fieldnum int result_id string field_name Pg_fieldnum will return the number of the column slot that corresponds to the named field in the given PosgreSQL result identifier. Field numbering starts at 0. This function will return -1 on error. pg_fieldprtlen Returns the printed length int pg_fieldprtlen int result_id int row_number string field_name Pg_fieldprtlen will return the actual printed length (number of characters) of a specific value in a PostgreSQL result. Row numbering starts at 0. This function will return -1 on an error. pg_fieldsize Returns the internal storage size of the named field int pg_fieldsize int result_id int field_number Pg_fieldsize will return the internal storage size (in bytes) of the field number in the given PostgreSQL result. Field numbering starts at 0. A field size of -1 indicates a variable length field. This function will return false on error. pg_fieldtype Returns the type name for the corresponding field number string pg_fieldtype int result_id int field_number Pg_fieldtype will return a string containing the type name of the given field in the given PostgreSQL result identifier. Field numbering starts at 0. pg_freeresult Free reult memory int pg_freeresult int result_id Pg_freeresult only needs to be called if you are worried about using too much memory while your script is running. All result memory will automatically be freed when the script is finished. But, if you are sure you are not going to need the result data anymore in a script, you may call pg_freeresult with the result identifier as an argument and the associated result memory will be freed. pg_getlastoid Returns the last object identifier int pg_getlastoid int result_id Pg_getlastoid can be used to retrieve the oid assigned to an inserted tuple if the result identifier is used from the last command sent via pg_exec and was an SQL INSERT. This function will return a positive integer if there was a valid oid. It will return -1 if an error occured or the last command sent via pg_exec was not an INSERT. pg_host Returns the host name associated with the connection string pg_host int connection_id Pg_host will return the host name of the given PostgreSQL connection identifier is connected to. pg_loclose Close a large object void pg_loclose int fd Pg_loclose closes an Inversion Large Object. Fd is a file descriptor for the large object from pg_loopen. pg_locreate Create a large object int pg_locreate int conn Pg_locreate creates an Inversion Large Object and returns the oid of the large object. conn specifies a valid database connection. PostgreSQL access modes INV_READ, INV_WRITE, and INV_ARCHIVE are not supported, the object is created always with both read and write access. INV_ARCHIVE has been removed from PostgreSQL itself (version 6.3 and above). pg_loexport Export a large object to file bool pg_loexport int oid int file int connection_id The oid argument specifies the object id of the large object to export and the filename argument specifies the pathname of the file. Returns FALSE if an error occurred, TRUE otherwise. Remember that handling large objects in PostgreSQL must happen inside a transaction. pg_loimport Import a large object from file int pg_loimport int file int connection_id The filename argument specifies the pathname of the file to be imported as a large object. Returns FALSE if an error occurred, object id of the just created large object otherwise. Remember that handling large objects in PostgreSQL must happen inside a transaction. pg_loopen Open a large object int pg_loopen int conn int objoid string mode Pg_loopen open an Inversion Large Object and returns file descriptor of the large object. The file descriptor encapsulates information about the connection. Do not close the connection before closing the large object file descriptor. objoid specifies a valid large object oid and mode can be either "r", "w", or "rw". pg_loread Read a large object string pg_loread int fd int len pg_loread reads at most len bytes from a large object and returns it as a string. fd specifies a valid large object file descriptor andlen specifies the maximum allowable size of the large object segment. pg_loreadall Read a entire large object and send straight to browser void pg_loreadall int fd Pg_loreadall reads a large object and passes it straight through to the browser after sending all pending headers. Mainly intended for sending binary data like images or sound. pg_lounlink Delete a large object void pg_lounlink int conn int lobjid Pg_lounlink deletes a large object with the lobjid identifier for that large object. pg_lowrite Write a large object int pg_lowrite int fd string buf Pg_lowrite writes at most to a large object from a variable buf and returns the number of bytes actually written, or false in the case of an error. fd is a file descriptor for the large object from pg_loopen. pg_numfields Returns the number of fields int pg_numfields int result_id Pg_numfields will return the number of fields (columns) in a PostgreSQL result. The argument is a valid result identifier returned by pg_exec. This function will return -1 on error. pg_numrows Returns the number of rows int pg_numrows int result_id Pg_numrows will return the number of rows in a PostgreSQL result. The argument is a valid result identifier returned by pg_exec. This function will return -1 on error. pg_options Get the options associated with the connection string pg_options int connection_id Pg_options will return a string containing the options specified on the given PostgreSQL connection identifier. pg_connect Open a PostgreSQL connection int pg_connect string conn_string Returns a connection index on success, or false if the connection could not be made. Opens a connection to a PostgreSQL database. The conn_string should be a quoted string. The arguments available include dbname port, host, tty, options, user, and password This function returns a connection index that is needed by other PostgreSQL functions. You can have multiple connections open at once. The previous syntax of: $conn = pg_pconnect ("host", "port", "options", "tty", "dbname") has been deprecated. See also pg_connect. pg_port Return the port number associated with the connection int pg_port int connection_id Pg_port will return the port number that the given PostgreSQL connection identifier is connected to. pg_result Returns values from a result identifier mixed pg_result int result_id int row_number mixed fieldname Pg_result will return values from a result identifier produced by pg_Exec. The row_number and fieldname sepcify what cell in the table of results to return. Row numbering starts from 0. Instead of naming the field, you may use the field index as an unquoted number. Field indices start from 0. PostgreSQL has many built in types and only the basic ones are directly supported here. All forms of integer, boolean and oid types are returned as integer values. All forms of float, and real types are returned as double values. All other types, including arrays are returned as strings formatted in the same default PostgreSQL manner that you would see in the psql program. pg_setclientencoding Set the client encoding int pg_setclientencoding int connection string encoding The function set the client encoding and return 0 if success or -1 if error. encoding is the client encoding and can be either : SQL_ASCII, EUC_JP, EUC_CN, EUC_KR, EUC_TW, UNICODE, MULE_INTERNAL, LATINX (X=1...9), KOI8, WIN, ALT, SJIS, BIG5, WIN1250. This function requires PHP-4.0.2 or higher and PostgreSQL-7.0 or higher. See also pg_clientencoding. pg_clientencoding Get the client encoding string pg_clientencoding int connection The functions returns the client encoding as the string. The returned string should be either : SQL_ASCII, EUC_JP, EUC_CN, EUC_KR, EUC_TW, UNICODE, MULE_INTERNAL, LATINX (X=1...9), KOI8, WIN, ALT, SJIS, BIG5, WIN1250. This function requires PHP-4.0.2 or higher and PostgreSQL-7.0 or higher. See also pg_setclientencoding. pg_trace Enable tracing a PostgreSQL connection bool pg_trace string filename string mode int connection Enables tracing of the PostgreSQL frontend/backend communication to a debugging file. To fully understand the results one needs to be familiar with the internals of PostgreSQL communication protocol. For those who are not, it can still be useful for tracing errors in queries sent to the server, you could do for example grep '^To backend' trace.log and see what query actually were sent to the PostgreSQL server. Filename and mode are the same as in fopen (mode defaults to 'w'), connection specifies the connection to trace and defaults to the last one opened. Returns TRUE if filename could be opened for logging, FALSE otherwise. See also fopen and pg_untrace. pg_tty Return the tty name associated with the connection string pg_tty int connection_id Pg_tty will return the tty name that server side debugging output is sent to on the given PostgreSQL connection identifier. pg_untrace Disable tracing of a PostgreSQL connection bool pg_untrace int connection Stop tracing started by pg_trace. connection specifies the connection that was traced and defaults to the last one opened. Returns always TRUE. See also pg_trace.