Add option :migrations-table-exists-sql for SQL backed migrations

[mbezjak]

Closes #157

[mbezjak]

Implemented the same thing in jdbc project. The PR should be complete now.

@weavejester Let me know what you think. Especially about the comment above.

[weavejester]

Thanks for the updated PR. Can you ensure all lines are 80 characters or less?

[mbezjak]

Updated as per comments. Thanks for looking into this. 😄

Can you ensure all lines are 80 characters or less?

Done. Although, there are some prior lines not respecting it.

$ grep -R '.\{81\}' next-jdbc/src/ jdbc/src/
next-jdbc/src/ragtime/next_jdbc.clj:      ;; Returns unqualified maps as some databases (e.g. Oracle) can only return them
next-jdbc/src/ragtime/next_jdbc.clj:      (rs/datafiable-result-set conn {:builder-fn rs/as-unqualified-lower-maps})))
next-jdbc/src/ragtime/next_jdbc.clj:  ;; Remove db quote around the schema and table name; ex.: "\"schema\".\"table\""

[mbezjak]

Ping 😄

[weavejester]

Apologies for the delay, this PR seems to have slipped through my inbox.

[weavejester]

I have some minor formatting suggestions. Once they're done could you squash down your commits and give them an appropriate commit message. Once again, apologies for not getting around to reviewing this.

[mbezjak]

Done! Thanks for looking at this. 😄

[weavejester]

Thanks! Can you change the commit message to:

Add :migrations-table-exists-sql option

Add a :migrations-table-exists-sql option in order to more efficiently
check for the Ragtime migrations table. Using database metadata lookups
via JDBC can be slow depending on the size of the database.

Fixes #157.

This is to ensure it adheres to the contributing guidelines. Once that's done I'll merge and cut a release. Thanks again for your patience.

[mbezjak]

Done! Thanks!