[sqlite] about attach database

[王庆刚]

hi,all
     There are two ways to open a database. 
     1.sqlite3_open
     2.ATTACH DATABASE

     Because there are so many data base. So we used attach database to open 
them.
     But the efficiency of the programming is not ideal.

     which one is faster? 
     Is the efficiency between the two methods great?

     best regards.
         wqg