execute方法（Execute method）.docVIP

execute方法（Execute method） Using the method of execute The execute method should be combined to return multiple ResultSet objects, a ResultSet object and update the update count or count only in the statement of the use of. When performing a stored procedure or dynamic execution of unknown SQL string (i.e. the application programmer is not known at compile time), there may be multiple results, although this is rare. For example, a user may execute a stored procedure (using the CallableStatement object - see page 135th CallableStatement), and the stored procedure can perform the update, and then selected to update, and then choose, etc.. Usually use stored procedures, people should know that it returns the content. Because execute unconventional, so get some special treatment and not need the result. For example, assume that a known procedure returns two results, in the method of using execute to execute the procedure, you must call the getResultSet method to obtain the first result set, and then call the getXXX method to get the proper value. To get the second set of results, need to call the getMoreResults method, and then call the getResultSet method. If a process known to return the two update count, first call the getUpdateCount method, and then call getMoreResults, and call getUpdateCount again. Who do not know what to return, the situation is more complex. If the result is ResultSet, then the method execute returns true; if the result is Java int, returns false. If it returns int, it means that the result is the update count or execution of the statement is DDL command. The first thing to do after the execute call method is to call getResultSet or getUpdateCount. Calling the getResultSet method can get the first object of two or more ResultSet objects; or call the method getUpdateCount can be the first update count content to get two or more update counts. When the SQL statement is not the result of the result set, the method will return null getResultSet. This