add additional sqlite3 support for migrate and alter
Expanded support for SQLite3
Purpose: I use sqlite3 for my local prototyping and noticed that many small changes could be made to expand SQLite3 support.
Details:
- Added support for
not-null
,null
,default
,unique
,primary key
,auto-increment
,auto-now-once
for SQLite3. - Refactored the check for table existence to support valid syntax in MySQL, PostgreSQL, and SQLite3.
- Enabled alter table support with SQLite3 databases for renaming and dropping columns.