问题
I was wondering if there is a simple way to store meta information about an sqlite-Database in that database.
I am specifically thinking about a version number that lets you easily find out which version of a database layout you are using (So my code could check if the database structure is compatible without querying SELECT sql FROM sqlite_master WHERE type='table'; and comparing the result with a predefined schematic). To clarify: I am not interested in the version number of the sqlite software, but something akin to pythons __version__ variable that can be defined seperately for each python file.
I know that I can probably just create a table named "meta" and save it there, but I was wondering if there was a better way to do that.
I also know that checking compatibility by only checking a version number has some problems, and I will still do other checks if necessary, but for now I am only interested in the version number I described.
回答1:
You might want to check out the user_version pragma.
回答2:
SQLite offers two slots to store an integer as metadata.
application_id
https://www.sqlite.org/pragma.html#pragma_application_id
Set an application_id to 900
PRAGMA application_id = 900;
Get the application_id
PRAGMA application_id;
user_version
https://www.sqlite.org/pragma.html#pragma_user_version
Set an user_version to 901
PRAGMA user_version = 901;
Get the user_version
PRAGMA user_version;
来源：https://stackoverflow.com/questions/9555479/easy-way-to-store-metadata-about-sqlite-database