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For one of my applications I needed to determine the user_version of a database, without using the SQLite3 library.
This value is not used by SQLite3, but a user can use it to version their database. The default value is 0.
Setting this variable can be done in SQL with "PRAGMA user_version=x;" where "x" is an integer.
You can read the value with SQL as well: "PRAGMA user_version;".
In the SQLite3 specs it is defined as the integer at offset 60 (the bytes 60, 61, 62 and 63 = integer) in the database file.
So I wrote a quick function for this which returns an integer:
-1 : if the file does not exist
0 : if user_version was not set
x : the user_version value
Here is my function, hope this is useful to someone out there (uses SysUtils):
{
Retrieve database user version value without using a library, this is a raw file read!
This value can be set in SQlite using "PRAGMA user_version=x" where x = integer.
}
function GetSQLite3Database_UserVersion(filename:string):integer;
var
FileHandle:THandle;
dbUserVersion:array [1..4] of byte;
const
SQLite3_ByteOffset_UserVersion = 60; // see:
begin
Result := -1;
if FileExists(filename) then
begin
FileHandle:=FileOpen(filename,fmOpenRead);
if FileHandle<>-1 then
begin
FileSeek(FileHandle,SQLite3_ByteOffset_UserVersion,fsFromBeginning);
FileRead(FileHandle,dbUserVersion[1],SizeOf(dbUserVersion));
FileClose(FileHandle);
Result := ( dbUserVersion[1]<<24 ) + ( dbUserVersion[2]<<16 ) + ( dbUserVersion[3]<<8 ) + dbUserVersion[4];
end;
end;
end;