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PHP : Function Reference : PostgreSQL Functions : pg_meta_data

pg_meta_data

Get meta data for table (PHP 4 >= 4.3.0, PHP 5)
array pg_meta_data ( resource connection, string table_name )

Example 1954. Getting table metadata

<?php
 $dbconn
= pg_connect("dbname=publisher") or die("Could not connect");

 
$meta = pg_meta_data($dbconn, 'authors');
 if (
is_array($meta)) {
     echo
'<pre>';
     
var_dump($meta);
     echo
'</pre>';
 }
?>

The above example will output:

array(3) {
["author"]=>
array(5) {
 ["num"]=>
 int(1)
 ["type"]=>
 string(7) "varchar"
 ["len"]=>
 int(-1)
 ["not null"]=>
 bool(false)
 ["has default"]=>
 bool(false)
}
["year"]=>
array(5) {
 ["num"]=>
 int(2)
 ["type"]=>
 string(4) "int2"
 ["len"]=>
 int(2)
 ["not null"]=>
 bool(false)
 ["has default"]=>
 bool(false)
}
["title"]=>
array(5) {
 ["num"]=>
 int(3)
 ["type"]=>
 string(7) "varchar"
 ["len"]=>
 int(-1)
 ["not null"]=>
 bool(false)
 ["has default"]=>
 bool(false)
}
}

Code Examples / Notes » pg_meta_data

yarnofmoo

You can get some possibly more useful information with the query:
SELECT table_name, column_name, data_type, character_maximum_length FROM information_schema.columns WHERE table_name='tablename';


rburghol

When querying on meta data from a temp table, the meta data seems to persist even if a fresh connection is established, where the temp table no longer exists.
For example, if you create a connection and a temp table like so:
$dbconn1 = pg_connect('blah blah', , PGSQL_CONNECT_FORCE_NEW);
pg_exec($dbconn1,'create temp table foo as select 'foo' as namecol, 'bar' as valcol');
Then create a new connection
$dbconn2 = pg_connect('blah blah', , PGSQL_CONNECT_FORCE_NEW);
And query the meta data for table 'foo' in this new connection, it will report the facts about this table:
pg_meta_data($dbconn2,'foo');
"'Array ( [foo] => Array ( [num] => 1 [type] => varchar... "
However, trying to remove this table:
pg_exec($dbconn,'drop table foo');
Throws an error:
pg_exec(): Query failed: ERROR: table "foo" does not exist in ...


dmiller

This function seems to be case-sensitive on tablename (php-4.3.1)
The Array returned is of the following structure
['field name'] => Array
  (
    ['num'] => Field number starting at 1
    ['type'] => data type, eg varchar, int4
    ['len'] => internal storage size of field. -1 for varying
    ['not null'] => boolean
    ['has default'] => boolean
  )
    ......
for Varied size datatypes (varchar, text, etc)
you can get the max data length from the system table pg_attribute.atttypmod -4
eg.
select attnum, attname , atttypmod -4 as field_len
from pg_attribute, pg_class
where relname='$tablename'
and attrelid=relfilenode
and attnum>=1


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