Collection::existsInDatabase

Check if collection exists in database

&reftitle.description; public `bool` `mysql_xdevapi\Collection::existsInDatabase`

Checks if the Collection object refers to a collection in the database (schema).

&reftitle.parameters; &no.function.parameters;
&reftitle.returnvalues;

Returns &true; if collection exists in the database, else &false; if it does not.

A table defined with two columns (doc and _id) is considered a collection, and a third _json_schema column as of MySQL 8.0.21. Adding an additional column means existsInDatabase() will no longer see it as a collection.

&reftitle.examples;

### `mysql_xdevapi\Collection::existsInDatabase` example

    <?php
    $session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
    $session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
    $session->sql("CREATE DATABASE addressbook")->execute();

    $schema = $session->getSchema("addressbook");
    $create = $schema->createCollection("people");

    // ...

    $collection = $schema->getCollection("people");

    // ...

    if (!$collection->existsInDatabase()) {
        echo "The collection no longer exists in the database named addressbook. What happened?";
    }
    ?>