sqlite 内存数据库的attach

sqlite3_open(":memory:", &db);
...
ret = sqlite3_exec(db, "CREATE TABLE new_table1 (id integer primary key autoincrement,name vchar(32))", 0, 0, &zErrMsg);

ret = sqlite3_exec(db,"begin transaction",0,0,&zErrMsg);

ret = sqlite3_exec(db, "insert into new_table1 (name) values ('123');", 0, 0,&zErrMsg);

ret = sqlite3_exec(db,"commit transaction",0,0,&zErrMsg);



sqlite3_open("c:/A.dat", &db);
ret = sqlite3_exec(db,"attach 'c:/A.dat' as new_db",0,0,&zErrMsg);

ret = sqlite3_exec(db,"begin transaction",0,0,&zErrMsg);

ret = sqlite3_exec(db,"insert into new_db.new_table2 (name) select name from new_table1",0,0,&zErrMsg);

ret = sqlite3_exec(db,"commit transaction",0,0,&zErrMsg);

if (ret!=SQLITE_OK)
MessageBox("附加数据库失败！");

300万条内存数据,10个字段,大概写入了631MB物理文件