On Aug 3, 2018, at 12:52 PM, John R. Sowden <jsow...@americansentry.net> wrote: > > I have the xbase type of databases down tight
I’d be careful trying to apply your knowledge directly to SQLite. dBase comes out of the non-SQL world, so it’s going to have a different outlook in many areas. > I understand what an index is. If the following is a fair description of how FoxPro for DOS indexes work, then I question how well your knowledge transfers to SQLite: https://docs.microsoft.com/sql/odbc/microsoft/index-command Compare: https://sqlite.org/lang_createindex.html The Venn diagram of these two documentation pages seems to have a pretty small region of overlap. > how do I use a common index for the different database files. It makes no sense to talk about using an index across multiple SQLite DB files. The index data structure in SQLite has page offsets within that file, which is how SQLite uses the index to look up the data the index entry refers to. The same page offset in a different file will contain different data; the other file might not even *have* such a page number! A book’s index cannot be used to look up information in other books for the same reason. If a book’s index says the information you want is on page 42, it is not on page 42 in all books, only in *that* book. > I won't provide technicians with accounts receivable databases, etc. SQLite will let you put as many tables in a DB file as you want, from one table per DB file to all tables in one DB file, or anything in between. A SQLite-based application can attach to multiple database files using a single connection, so that the application that has legitimate need of accounts data can attach to that DB file, while other applications can attach to the DB file(s) it needs. https://www.sqlite.org/lang_attach.html > My thinking is along the line of all mission critical clocks take their > accuracy from the US Naval Observatory in Fort Collins, CO, instead of > thousands of free running clocks, each with what it thinks is the correct > time. I don’t see how that analogy applies to SQLite. I think my book analogy is a reasonable high-level approximation to the way SQLite indexes work, once created, at a static level. Once you start modifying data, the analogy breaks down, but then you can start to think about how a computerized book indexing program would work, and the analogy continues to function. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
