MySQL in a Nutshell, 2nd Edition

Name

HANDLER

Synopsis

HANDLER table OPEN [AS handle]
      
HANDLER handle READ index { = | >= | <= | < } (value,...) 
   [WHERE condition] [LIMIT ...]
   
HANDLER handle READ index {FIRST|NEXT|PREV|LAST} 
   [WHERE condition] [LIMIT ...]
   
HANDLER handle READ {FIRST|NEXT} 
   [WHERE condition] [LIMIT ...]
    
HANDLER handle CLOSE

A handle provides direct access to a table, as opposed to working from a results set. Handles can be faster than SELECT statements when reading large numbers of rows from a table. MyISAM and InnoDB tables currently support handlers.

A handle is usable only by the session (connection thread) that established it. The table is still accessible by other sessions, though, and is not locked by this statement. Because of this, and because the method provides direct table access, the data in the table can change and even be incomplete as the handler performs successive reads.

Create a handler by issuing a HANDLER statement with the OPEN clause to establish a handle for the table, much like a file handle in a programming language such as Perl. The AS clause and handle name are optional. If an alias is not given, the table name is used as the handler name for subsequent HANDLER statements.

You can then use HANDLER statement formats with READ clauses to read data from a table. Finish by issuing HANDLER with a CLOSE clause.

Here are a couple of basic examples of the HANDLER statement:

HANDLER clients OPEN AS clients_handle;
HANDLER clients_handle READ FIRST;

The first line creates the table handle called ...