Schema Migration Support

[anshum4n-git]

Currently, schema migration would be manual. However, given an updated pydantic schema and a schema DDL script ( #6 ) a command line can be provided that generates migration scripts. These can follow the Django migration pattern which creates a migration and then applies it, also storing in the database which migrations have been applied and which haven't.

[ojasaklechat41]

@anshum4n-git

• I think this issue depends upon Schema Lookup support #8 as well, as we will be requiring to lookup on the existing schema to make the migrations.

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Proposed Migration Procedure

1. Check existing table query or DB schema lookup using (Schema Lookup support #8).
2. Check for the new changes in the Pydantic schema.
3. Generate the SQL query based on the delta between the Pydantic schema and the actual DB schema.

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Data Migration Concerns

• While doing the migration, how are we going to make migration of data as well?

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Migration History Storage

• To store the data migration history, I think we could cache the migration data in our project files only, just like we cache the generated DB queries.
• We could store the previous schema or its delta in a folder, while storing its metadata like timestamp, etc. in the DB in a new table.