mysql_field_flags

(PHP 4, PHP 5)

mysql_field_flags — Liefert die Flags des angegebenen Feldes aus einem Abfrageergebnis

Warnung

Diese Erweiterung ist seit PHP 5.5.0 als veraltet markiert und wurde in PHP 7.0.0 entfernt. Verwenden Sie stattdessen die Erweiterungen MySQLi oder PDO_MySQL. Weitere Informationen bietet der Ratgeber MySQL: Auswahl einer API. Alternativen zu dieser Funktion umfassen:

mysqli_fetch_field_direct() [flags]
PDOStatement::getColumnMeta() [flags]

Beschreibung

mysql_field_flags(resource $result, int $field_offset): string|false

mysql_field_flags() gibt die Flags des Feldes am übergebenen Offset zurück. Die Flags werden als einzelne Worte pro Flag und durch ein einziges Leerzeichen getrennt zurückgegeben, sodass sie einfach mit explode() getrennt werden können.

Parameter-Liste

result: Das Ergebnis Ressource, das ausgewertet wird. Dieses Ergebnis kommt von einem Aufruf von mysql_query().
field_offset: Der numerische Offset des Feldes. Der field_offset beginnt bei 0. Falls field_offset nicht existiert, wird eine Warnung der Stufe E_WARNING erzeugt.

Rückgabewerte

Gibt eine Zeichenkette aus Flags zurück, die mit dem Ergebnis assoziiert sind. Bei einem Fehler wird false zurückgegeben.

Die folgenden Flags werden zurückgegeben, wenn Ihre Version von MySQL aktuell genug ist, diese zu unterstützen: "not_null", "primary_key", "unique_key", "multiple_key", "blob", "unsigned", "zerofill", "binary", "enum", "auto_increment" und "timestamp".

Beispiele

Beispiel #1 Ein mysql_field_flags()-Beispiel

<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
    echo 'Konnte die Abfrage nicht ausführen: ' . mysql_error();
    exit;
}
$flags = mysql_field_flags($result, 0);

echo $flags;
print_r(explode(' ', $flags));
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

not_null primary_key auto_increment
Array
(
    [0] => not_null
    [1] => primary_key
    [2] => auto_increment
)

Anmerkungen

Hinweis:
Für die Abwärtskompatibiliät kann der folgende veraltete Alias verwendet werden: mysql_fieldflags()

Siehe auch

mysql_field_type() - Liefert den Typ des spezifizierten Feldes aus einem Ergebnis
mysql_field_len() - Liefert die Länge des angegebenen Feldes

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User Contributed Notes 10 notes

down

amir at scrounch dot com ¶

21 years ago

returns primary keys of a table using 'show keys'

although it is possible to use desc, show keys offers possible enhancements such a getting sequence in index along with it



function getPrimaryKeyOf($table, $link) {

  $pk = Array(); 



  $sql = 'SHOW KEYS FROM `'.$table.'`'; 

  $res = mysql_query($table, $link) or die(mysql_error()); 

  while ($row = mysql_fetch_assoc($res)) { 

    if ($row['Key_name']=='PRIMARY') 

      array_push($pk, $row['Column_name']); 

  } 

  return $pk; 

}

down

cufarley at nirvanet dot net ¶

23 years ago

Using the "DESC TableName" command may also do the trick and is a bit shorter.

down

play at arcadevillage dot com ¶

15 years ago

To really backup the database values, I made a little changement :



My code really looks like bomas 's code, but there is an important diffence :



<?php

$nbc = mysql_num_fields($req_table);

while ($ligne = mysql_fetch_array($req_table))

  {

    $insertions = "INSERT INTO $table VALUES(";

     for ($i=0; $i<$nbc; $i++)

        {

          if ( $i > 0 ) $insertions .= ", ";

          if ( !isset($ligne[$i])) 

            $insertions .= "NULL";

          else

            $insertions .= "'" . mysql_real_escape_string($ligne[$i]). "'";

        }

     $insertions .= ");";

     $dumpsql[] = $insertions;

   }

?>



$dumpslq is the variable where I put the insertion orders before writting them in a text file.



Before, I test that the values if not NULL into the field because it is the only way to make the difference, for example for string text fields, between NULL values and empty strings.



If you don't make this test, you should find empty string instead of NULL values when you do the backup.

down

pike-php at kw dot nl ¶

19 years ago

ok, sorry for the code bloat :) but this is how I 
get the full power of mysql's DESCRIBE table statement, in 
an associative array, including defaults, enum values, float radix et all.

it assumes mysql returns the type as 
   "type[(arg[,arg..])] [ add]"
like
   "float(20,6) unsigned"
   "enum('yes','no')"
etc

<?

function getFields($tablename) {
    
        $fields = array();
        $fullmatch         = "/^([^(]+)(\([^)]+\))?(\s(.+))?$/";
        $charlistmatch     = "/,?'([^']*)'/";
        $numlistmatch     = "/,?(\d+)/";
        
        $fieldsquery .= "DESCRIBE $tablename";
        $result_fieldsquery = mysql_query($fieldsquery) or die(mysql_error());
        while ($row_fieldsquery = mysql_fetch_assoc($result_fieldsquery)) {
            
            $name     = $row_fieldsquery['Field'];
            $fields[$name] = array();
            $fields[$name]["type"]         = "";
            $fields[$name]["args"]         = array();
            $fields[$name]["add"]          = "";
            $fields[$name]["null"]        = $row_fieldsquery['Null'];
            $fields[$name]["key"]        = $row_fieldsquery['Key'];
            $fields[$name]["default"]    = $row_fieldsquery['Default'];
            $fields[$name]["extra"]        = $row_fieldsquery['Extra'];
            
            $fulltype     = $row_fieldsquery['Type'];
            $typeregs = array();
            
            if (preg_match($fullmatch, $fulltype, $typeregs)) {
                $fields[$name]["type"] = $typeregs[1];
                if ($typeregs[4]) $fields[$name]["add"] = $typeregs[4];
                $fullargs = $typeregs[2];
                $argsreg = array();
                if (preg_match_all($charlistmatch, $fullargs, $argsreg)) {
                    $fields[$name]["args"] = $argsreg[1];
                } else {
                    $argsreg = array();
                    if (preg_match_all($numlistmatch, $fullargs, $argsreg)) {
                        $fields[$name]["args"] = $argsreg[1];
                    } else die("cant parse type args: $fullargs");
                }
            } else die("cant parse type: $fulltype");

        }
        return $fields;
            
    }

?>

down

simone dot t at betisgroup dot com ¶

21 years ago

Another examples :

####################################

function field_keys($host, $user, $password, $database, $field ) {
   $db_link = mysql_connect($host, $user, $password) or die ("error connect");
   mysql_select_db($database,$db_link);
   $query="DESC $field";
   $results=mysql_query($query);
   $i=0;
   while ($row=mysql_fetch_array($results)) {
         if ($row[Key]=="PRI") {
            $array_keys[$i]=$row[Field];
         }
         $i++;
  }
   return $array_keys;
}

####################################

//Example of Main...
$tmp = field_keys("localhost", "myuser", "mypassword", "mydb", "field_name" );

// ...loop through array...
foreach ( $tmp as $array_tmp){
    print "<br>";
    print $array_tmp;
    print "<br>";
}

down

jakemsr at jakemsr dot com ¶

22 years ago

I didn't find anything to get the valid values for
ENUM or SET column types, so I came up with the
following

function mysql_enum_values($table, $field)
{
    $sql = "SHOW COLUMNS FROM $table LIKE '$field'";
    $sql_res = mysql_query($sql)
        or die("Could not query:\n$sql");
    $row = mysql_fetch_assoc($sql_res);
    mysql_free_result($sql_res);
    return(explode("','",
        preg_replace("/.*\('(.*)'\)/", "\\1",
            $row["Type"])));
}

down

-1

bomas at cities-of-faith dot com ¶

19 years ago

well, to make a complete backup of your database, i suggest this code:

//open database here
$tab_status = mysql_query("SHOW TABLE STATUS");
while($all = mysql_fetch_assoc($tab_status)):
    $tbl_stat[$all[Name]] = $all[Auto_increment];
endwhile;
unset($backup);
$tables = mysql_list_tables('cofadmin');
while($tabs = mysql_fetch_row($tables)):
    $backup .= "--\n--Tabel structuur voor `$tabs[0]`\n--\n\nDROP IF EXISTS TABLE `$tabs[0]`\nCREATE TABLE IF NOT EXISTS `$tabs[0]` (&nbsp;";
    $res = mysql_query("SHOW CREATE TABLE $tabs[0]");
    while($all = mysql_fetch_assoc($res)):
        $str = str_replace("CREATE TABLE `$tabs[0]` (", "", $all['Create Table']);
        $str = str_replace(",", ",&nbsp;", $str);
        $str2 = str_replace("`) ) TYPE=MyISAM ", "`)\n ) TYPE=MyISAM ", $str);
        $backup .= $str2." AUTO_INCREMENT=".$tbl_stat[$tabs[0]].";\n\n";
    endwhile;
    $backup .= "--\n--Gegevens worden uitgevoerd voor tabel `$tabs[0]`\n--\n\n";
    $data = mysql_query("SELECT * FROM $tabs[0]");
    while($dt = mysql_fetch_row($data)):
        $backup .= "INSERT INTO `$tabs[0]` VALUES('$dt[0]'";
        for($i=1; $i<sizeof($dt); $i++):
            $backup .= ", '$dt[$i]'";
        endfor;
        $backup .= ");\n";
    endwhile;
    $backup .= "\n-- --------------------------------------------------------\n\n";
endwhile;
echo $backup;

this displayes your data the same way as phpmyadmin does.

hope it helps some of you guys
Greetz

down

-1

justin DOT flavin AT ntlworld DOT com ¶

22 years ago

Sometimes, when writing a generic function or class, you want your script to be able to determine what the primary key of a table is. 
/* usual MySQL stuff */
$query="DESC UsersTable";
$results=mysql_query($query);

while ($row=mysql_fetch_array($results))
{
if ($row[Type]="PRI")
    {
print "I found the primary key! <br>";
$UserKey=$row[Field];
print $row[Field];
/* drop out , as we've found the key */    
exit;
    }
}

..... later on we might have something like

< some sort of loop through records >

print "<a href='View_User_record.php?userkey=$UserKey'> Users Name </a>";

<end loop>

What's also interesting is the useful data you can get from
a DESC query.

The following prints out the array values grabbed by mysql_fetch_array on a DESC query - VERY useful stuff!!!

/* usual MySQL stuff */
$query="DESC UsersTable";
$results=mysql_query($query);

while ($row=mysql_fetch_array($results))
{
print "<pre>";
print_r ($row);
print "</pre>";
}

down

-1

buttrose at unimelb dot edu dot au ¶

20 years ago

This function is essential for writing a generic table editor (ie one that just takes the name of the table and works out what fields it has, types, sizes etc.). Unfortunately, I am using psotgreSQL not mySql. Postgres has field_type and field_size functions  but not as far as I can tell an equivalent of the mysql_field_flags() function. Without it, there is no way I can do generic ADDs and INSERTs. 

Anyone know a workaround to get this information (eg is the field a primary key? Can it be NULL? Is it auto_increment?) in Postgres?

Cheers

Rob Buttrose

down

-2

jurgen at alienguitar dot com ¶

23 years ago

The previous problem to get the default values of a column:

Use the following query and parse the 'Default' column:



"SHOW COLUMNS FROM TableName"



or for a single entry:



"SHOW COLUMNS FROM TableName LIKE 'column'"



It will give you also values for Type,  Null, Key and Extra (check with mysql program first, so you see what you get ;-)

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