Db_RecordExists and Db_NoRecordExists
Zend_Validate_Db_RecordExists and
Zend_Validate_Db_NoRecordExists provide a means to test
whether a record exists in a given table of a database, with a given
value.
Basic usage
An example of basic usage of the validators:
isValid($emailaddress)) {
// email address appears to be valid
} else {
// email address is invalid; print the reasons
foreach ($validator->getMessages() as $message) {
echo "$message\n";
}
}
]]>
The above will test that a given email address is in the database
table. If no record is found containing the value of
$emailaddress in the specified column, then an error
message is displayed.
isValid($username)) {
// username appears to be valid
} else {
// username is invalid; print the reason
$messages = $validator->getMessages();
foreach ($messages as $message) {
echo "$message\n";
}
}
]]>
The above will test that a given username is not in the database
table. If a record is found containing the value of
$username in the specified column, then an error
message is displayed.
Excluding records
Zend_Validate_Db_RecordExists and
Zend_Validate_Db_NoRecordExists also provide a means
to test the database, excluding a part of the table, either by
providing a where clause as a string, or an array with the keys
"field" and "value".
When providing an array for the exclude clause, the !=
operator is used, so you can check the rest of a table for a value
before altering a record (for example on a user profile form)
getId();
$validator = new Zend_Validate_Db_NoRecordExists(
'users',
'username',
array(
'field' => 'id',
'value' => $user_id
)
);
if ($validator->isValid($username)) {
// username appears to be valid
} else {
// username is invalid; print the reason
$messages = $validator->getMessages();
foreach ($messages as $message) {
echo "$message\n";
}
}
]]>
The above example will check the table to ensure no records other
than the one where id = $user_id contains the value
$username.
You can also provide a string to the exclude clause so you can use
an operator other than !=. This can be useful for
testing against composite keys.
getId();
$clause = $db->quoteInto('post_id = ?', $category_id);
$validator = new Zend_Validate_Db_RecordExists(
'posts_categories',
'post_id',
$clause
);
if ($validator->isValid($username)) {
// username appears to be valid
} else {
// username is invalid; print the reason
$messages = $validator->getMessages();
foreach ($messages as $message) {
echo "$message\n";
}
}
]]>
The above example will check the posts_categories table
to ensure that a record with the post_id has a value
matching $category_id
Database Adapters
You can also specify an adapter, as the fourth parameter when
instantiating your validator, this will allow you to work with
applications using multiple database adapters, or where you have not
set a default adapter. As in the example below: