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PHP mysql_fetch_field() Function


PHP MySQL Reference Complete PHP MySQL Reference

Definition and Usage

The mysql_fetch_field() function returns an object containing information of a field from a recordset.

This function gets field data from the mysql_query() function and returns an object on success, or FALSE on failure or when there are no more rows.

Possible return values:

  • name - Field name
  • table - The table the field belongs to
  • def - Default value for the field
  • max_length - Maximum field length
  • not_null - 1 if the field cannot be NULL
  • primary_key - 1 if the field is a primary key
  • unique_key - 1 if the field is a unique key
  • multiple_key - 1 if the field is a non-unique key
  • numeric - 1 if the field is numeric
  • blob - 1 if the field is a BLOB
  • type - Field type
  • unsigned - 1 if the field is unsigned
  • zerofill - 1 if the field is zero-filled

Syntax

mysql_fetch_field(data,field_offset)

Parameter Description
data Required. Specifies which data pointer to use. The data pointer is the result from the mysql_query() function
field_offset Optional. Specifies which field to start returning. 0 indicates the first field. If this parameter is not set, it will retrieve the next field


Tips and Notes

Note: Each subsequent call to mysql_fetch_field() returns the next field in the recordset.


Example

<?php
$con = mysql_connect("localhost", "peter", "abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

$db_selected = mysql_select_db("test_db",$con);

$sql = "SELECT * from Person";
$result = mysql_query($sql,$con);

while ($property = mysql_fetch_field($result))
  {
  echo "Field name: " . $property->name . "<br />";
  echo "Table name: " . $property->table . "<br />";
  echo "Default value: " . $property->def . "<br />";
  echo "Max length: " . $property->max_length . "<br />";
  echo "Not NULL: " . $property->not_null . "<br />";
  echo "Primary Key: " . $property->primary_key . "<br />";
  echo "Unique Key: " . $property->unique_key . "<br />";
  echo "Mutliple Key: " . $property->multiple_key . "<br />";
  echo "Numeric Field: " . $property->numeric . "<br />";
  echo "BLOB: " . $property->blob . "<br />";
  echo "Field Type: " . $property->type . "<br />";
  echo "Unsigned: " . $property->unsigned . "<br />";
  echo "Zero-filled: " . $property->zerofill . "<br /><br />";
  }

mysql_close($con);
?>

The output of the code above could be:

Field name: LastName
Table name: Person
Default value:
Max length: 8
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 0
BLOB: 0
Field Type: string
Unsigned: 0
Zero-filled: 0

Field name: FirstName
Table name: Person
Default value:
Max length: 7
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 0
BLOB: 0
Field Type: string
Unsigned: 0
Zero-filled: 0

Field name: Address
Table name: Person
Default value:
Max length: 9
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 0
BLOB: 0
Field Type: string
Unsigned: 0
Zero-filled: 0

Field name: Age
Table name: Person
Default value:
Max length: 2
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 1
BLOB: 0
Field Type: int
Unsigned: 0
Zero-filled: 0


PHP MySQL Reference Complete PHP MySQL Reference

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