PHP - Manual: mysql_field_flags

2024-12-22

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mysql_field_flags

(PHP 4, PHP 5)

mysql_field_flags — 从结果中取得和指定字段关联的标志

说明

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

mysql_field_flags() 返回指定字段的字段标志。每个标志都用一个单词表示，之间用一个空格分开，因此可以用 explode() 将其分开。

如果 MySQL 版本足够新，则会支持以下的标志："not_null", "primary_key", "unique_key", "multiple_key", "blob", "unsigned", "zerofill", "binary", "enum", "auto_increment", "timestamp"。

为向下兼容仍然可以使用 mysql_fieldflags()，但反对这样做。

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User Contributed Notes 10 notes

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amir at scrounch dot com ¶

18 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; 

}

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cufarley at nirvanet dot net ¶

20 years ago


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

down

pike-php at kw dot nl ¶

16 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;
            
    }

?>

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play at arcadevillage dot com ¶

12 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.

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simone dot t at betisgroup dot com ¶

19 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>";
}

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jakemsr at jakemsr dot com ¶

19 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"])));
}

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-1

bomas at cities-of-faith dot com ¶

16 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

buttrose at unimelb dot edu dot au ¶

17 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

justin DOT flavin AT ntlworld DOT com ¶

19 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>";
}

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-3

jurgen at alienguitar dot com ¶

21 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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官方地址：https://www.php.net/manual/en/function.mysql-field-flags.php

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mysql_field_flags

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