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mysql_field_flags Ottine i flag associati al campo specificato di un risultato


string mysql_field_flags ( resource $risultato , int $indice_campo )

mysql_field_flags() restituisce i flag del campo specificato. I flag sono restituiti come singole parole per flag separate da un singolo spazio, in modo che sia possibile suddividere il valore restituito usando explode().

I seguenti flag sono restituiti, se la versione di MySQL è abbastanza aggiornata da supportarli: "not_null", "primary_key", "unique_key", "multiple_key", "blob", "unsigned", "zerofill", "binary", "enum", "auto_increment", "timestamp".

Per motivi di compatibilità con il passato, anche mysql_fieldflags() può essere usata. Questo comunque è sconsigliato.

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User Contributed Notes 10 notes

pike-php at kw dot nl
9 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]"
   "float(20,6) unsigned"


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;

amir at scrounch dot com
10 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;
jakemsr at jakemsr dot com
11 years ago
I didn't find anything to get the valid values for
ENUM or SET column types, so I came up with the

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);
        preg_replace("/.*\('(.*)'\)/", "\\1",
cufarley at nirvanet dot net
13 years ago
Using the "DESC TableName" command may also do the trick and is a bit shorter.
play at arcadevillage dot com
4 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 :

= 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(
$insertions .= "NULL";
$insertions .= "'" . mysql_real_escape_string($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.
buttrose at unimelb dot edu dot au
9 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?


Rob Buttrose
justin DOT flavin AT ntlworld DOT com
11 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";

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

..... 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";

while ($row=mysql_fetch_array($results))
print "<pre>";
print_r ($row);
print "</pre>";
bomas at cities-of-faith dot com
8 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];
$tables = mysql_list_tables('cofadmin');
while($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";
    $backup .= "--\n--Gegevens worden uitgevoerd voor tabel `$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]'";
        $backup .= ");\n";
    $backup .= "\n-- --------------------------------------------------------\n\n";
echo $backup;

this displayes your data the same way as phpmyadmin does.

hope it helps some of you guys
simone dot t at betisgroup dot com
11 years ago
Another examples :


function field_keys($host, $user, $password, $database, $field ) {
   $db_link = mysql_connect($host, $user, $password) or die ("error connect");
   $query="DESC $field";
   while ($row=mysql_fetch_array($results)) {
         if ($row[Key]=="PRI") {
   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>";
jurgen at alienguitar dot com
13 years ago
The previous problem to get the default values of a column:
Use the following query and parse the 'Default' column:


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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