Allow SQL migrations to take multiple commands about ragtime

[ragnard]

I think having the migrations be plain SQL files is very valuable. It means I can open them in my editor, edit the contents in the best way my editor can provide, get syntax highlightning, helpful formattting, maybe completion when connected to a database, execute statements line-by-line REPL style, etc. As soon as we stuff SQL text in a string we lose all that.

Have you considered the option of allowing multiple files per up/down migration, executed as separate commands in order by some sequence identifier? For example:

20120903221323-add-test-table.up.1.sql
20120903221323-add-test-table.up.2.sql
20120903221323-add-test-table.up.3.sql

[weavejester]

That's an interesting suggestion. Perhaps the syntax can be determined from the filename. So:

• \.edn$
• \.(up|down)\.sql$
• \.(up|down)\.\d+\.sql$

The reason I might still keep the edn syntax is that it's more concise and needs little code. Additionally, if a multimethod is used based on the file extension, other formats can be supported.

[ragnard]

I'm all for supporting different formats, I appreciate my views are biased by my particular workflow etc so having this open to extension (with EDN and sql in the box) would be great.

Not exactly sure what the extension point would look like. Might be a challenge to just dispatch on extension as the SQL format with multiple files per migration would need to consider a set of files and order them. But I don't know what the logic for loading files currently looks like.

[weavejester]

We just take a list of files, group them by extension, and then send each group to a multimethod.

[timvisher]

I generally stick to one statement per file and just use the normal sequencing method to get this behavior. What's the intrinsic value in providing multiple statements in a file?

[weavejester]

Grouping statements allows the migration to be considered atomically. If one statement fails, the whole migration fails.

[timvisher]

Ah. Yeah that makes sense. I guess I haven't been doing much DML with ragtime yet. That use case wasn't in my head.

[weavejester]

Done (99edc4c).