changeTableSql

Syntax

array changeTableSql (
    string $tableName,
    string $fields,
    optional array $tableOptions=false,
    optional bool $dropColumns=false
    )

Description

The method changeTableSql() creates the SQL statement necessary to make basic changes to a table in the database and populates it with columns defined in $fields option. If the table does not exist, it behaves like createTableSql(). In order to change the table, the output of the command must be executed with the executeSqlArray() method.

Parameters

$tableName

The table name must not yet exist in the database. Names must conform to any database specific requirements such as length limitations and name casing.

$fields is a string, not an array

$fields

A string holding information regarding the columns to create in the new table. For a detailed description of the format of this string, see Dictionary Column Attributes.

$tableOptions

An optional array of information that adds information regarding the table creation. This array may also contain field specific information, for example information pertaining to auto-increment fields.

$dropColumns

By default, any columns not specified in the $fields parameter are not changed. If the value of $dropColumns is set to true, then any column not specified in that value will be dropped.

Usage

/*
* create a data dictionary object, using the database connection
*/
$dict = NewDataDictionary($db);
 
$tabname = "LCTABLE";
/*
 * Change the length of COL1 from 32 chars to 60
 */
 
$flds = " 
   COL1 C(60) NOTNULL DEFAULT 'abc'
  ";
 
/*
* create the SQL statement necessary to create the table and its columns
*/
$sqlarray = $dict->changeTableSQL($tabname, $flds);
 
/*
 * This returns (for DB2)
Array
(
    [0] =>  ALTER TABLE LCTABLE 
            ALTER COLUMN COL1 SET DATA TYPE VARCHAR(60) DEFAULT 'abc'
)
*/
 
 
/*
* This statement actually creates the table
*/
$dict->executeSqlArray($sqlarray);