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';
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
pg_meta_data — 获得表的元数据
pg_metadata() 以数组形式返回 table_name 的表定义。
| 版本 | 说明 |
|---|---|
| 8.1.0 |
现在 connection 参数接受 PgSql\Connection
实例，之前接受 resource。
|
示例 #1 取得表的元数据
<?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>';
}
?>以上示例会输出：
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)
}
}
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';If parameter $extended not false:<?phparray (size=2) 'name' => array (size=11) 'num' => int 1 'type' => string 'varchar' (length=7) 'len' => int -1 'not null' => boolean false 'has default' => boolean true 'array dims' => int 0 'is enum' => boolean false 'is base' => boolean true 'is composite' => boolean false 'is pesudo' => boolean false 'description' => string '' (length=0) 'id' => array (size=11) 'num' => int 2 'type' => string 'int4' (length=4) 'len' => int 4 'not null' => boolean true 'has default' => boolean true 'array dims' => int 0 'is enum' => boolean false 'is base' => boolean true 'is composite' => boolean false 'is pesudo' => boolean false 'description' => string '' (length=0)?>To specify a schema as well as a table name, use the "schemaname.tablename" form as usual for PostgreSQL and the other functions in this extension. Without the prefix, of course, the default schema search path is used.<?php $meta = pg_meta_data($dbconn, 'foo.bar'); // table "bar" in schema "foo" if (is_array($meta)) { var_dump($meta); }?>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 -4eg. select attnum, attname , atttypmod -4 as field_len from pg_attribute, pg_class where relname='$tablename' and attrelid=relfilenode and attnum>=1When querying on meta data from a temp table, the meta data seems to persist even if a fresh connection is established, where the temp table no longer exists. For example, if you create a connection and a temp table like so:$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 ...The built in function does not provide any support for selecting a schema. If you need schema support and do not want to alter your SEARCH_PATH, the following function can provide it: function meta_data($table, $schema = 'public') {$result = pg_query_params("SELECT a.attname, a.attnum, t.typname, a.attlen, a.attnotNULL, a.atthasdef, a.attndims FROM pg_class as c, pg_attribute a, pg_type t, pg_namespace nWHERE a.attnum > 0 AND a.attrelid = c.oid AND c.relname = $1AND a.atttypid = t.oid AND n.oid = c.relnamespaceAND n.nspname = $2ORDER BY a.attnum", array($table, $schema));$fields = array();while($row = pg_fetch_array()) {$fields['attname'] = $row;} return $fields; }