Checks if a database exists on the MySQL server.

    CLI Example:

    .. code-block:: bash

        salt '*' mysql.db_exists 'dbname'

def db_exists(name, **connection_args):
    '''
    Checks if a database exists on the MySQL server.

    CLI Example:

    .. code-block:: bash

        salt '*' mysql.db_exists 'dbname'
    '''
    dbc = _connect(**connection_args)
    if dbc is None:
        return False
    cur = dbc.cursor()
    # Warn: here db identifier is not backtyped but should be
    #  escaped as a string value. Note also that LIKE special characters
    # '_' and '%' should also be escaped.
    args = {"dbname": name}
    qry = "SHOW DATABASES LIKE %(dbname)s;"
    try:
        _execute(cur, qry, args)
    except MySQLdb.OperationalError as exc:
        err = 'MySQL Error {0}: {1}'.format(*exc.args)
        __context__['mysql.error'] = err
        log.error(err)
        return False
    cur.fetchall()
    return cur.rowcount == 1