17.5. Training operator

  <prepare statement> :: =
    PREPARE <SQL statement name>
    FROM <SQL statement variable>
 <SQL statement variable> :: = <simple target specification>
 <preparable statement> :: =
   <preparable SQL data statement>
 |  <preparable SQL schema statement>
 |  <preparable SQL transaction statement>
 |  <preparable SQL session statement>
 |  <preparable implementation-defined statement>
 <preparable SQL data statement> :: =
   <delete statement: searched>
 |  <dynamic single row select statement>
 |  <insert statement>
 |  <dynamic select statement>
 |  <update statement: searched>
 |  <preparable dynamic delete statement: positioned>
 |  <preparable dynamic update statement: positioned>
 <preparable SQL schema statement> :: = <SQL schema statement>
 <preparable SQL transaction statement> :: = <SQL transaction statement>
 <preparable SQL session statement> :: = <SQL session statement>
 <dynamic select statement> :: = <cursor specification>
 <dynamic simple row select statement> :: = <query specification>
 <SQL statement name> :: = <statement name> |  <extended statement name>
 <extended statement name> :: = [scope option] <simple value specification>
 <cursor specification> :: =
   <query expression> [<order by clause>]
   [<updatability clause>]
 <updatability clause> :: =
    FOR {READ ONLY |  UPDATE [OF <column name list>]}
 <query expression> :: =
   <non-join query expression>
 |  <joined table>
 <query specification> :: =
    SELECT [<set quantifier>]
   <select list> <table expression>
 <set quantifier> :: = DISTINCT |  ALL 

Comment:

The PREPARE statement causes the compilation and construction of the execution plan of the SQL statement specified in the text form. After the successful execution of the PREPARE statement, the specified (literally or indirectly) name of this statement is associated with the prepared statement, which can then be used in the DESCRIBE, EXECUTE, OPEN CURSOR, ALLOCATE CURSOR and DEALLOCATE PREPARE statements. This association is maintained until the DEALLOCATE PREPARE statement is executed explicitly.