Hello! В сообщении от Saturday 02 August 2008 02:40:28 Dwight Ingersoll написал(а): > SQLite specific. For example, when/why would one choose to attach database > files over having the scheme reside in one database file, performance > considerations when databases are attached vs. single file databases.
For example, we have customers database with a lot of tables: users, user_preferences, regions, sales_points, etc. The database may be a little - a few dozens megabytes. And we have a monthly sales databases - one month may be a lot of gigabytes. So we open main small database and attach one of monthly big databases if needed. For yearly reports we can attach monthly databases in same order and process data incremental. I'm using main in-memory database and attach work database to it. Tables from work database may be replicated to in-memory database and processed. So work database isn't blocked at all process time and sql-queries on small replicated tables work fine. For big reports I'm attaching current user database (for examples, user 'user_1' have unique id equal 1 and so user database is users/1.db) and replicated tables is creating in user database. User database is permanent and user can work with his reports at continuous time from web-interface. Remember that writing to big databases may to allocate a lot of RAM (see detailed description on sqlite.org) and this operation is better doing in packet mode. Best regards, Alexey. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
