Fully support multi-dimensional arrays

[roji]

Single-dimensional PostgreSQL arrays are well-supported, but not multi-dimensional ones. This issue is meant to see how many people actually want this - please upvote if you'd benefit from it.

Things that need to be implemented:

• Literal value generation
• ValueComparer (comparison and snapshotting)
• PostgresArrayIndexExpression needs to have multiple indexes, just like .NET ArrayIndexExpression
• Full querability as a primitive collection?

[alexzaytsev-newsroomly]

@roji The documentation here: http://www.npgsql.org/efcore/mapping-and-translation.html says However, operations such as indexing the array, searching for elements in it, etc. aren't yet translated to SQL and will be evaluated client-side. This will probably be fixed in 1.2.
Since the latest version is over 2.0, i wanted to check - is something like

context.MyEntities.FirstOrDefault(x => x.ArrayProperty.Any(i => i == 42)) expected to be evaluated client side or actually sent to the backend?

(i noticed that Contains() is listed as supported on the same page)

[roji]

Will fix the docs, thanks. Yes, array operation translation was added to 2.0, which means server-evaluation (see #120). The translation list on the docs page is correct, I'll remove the old sentence you spotted. If you run into any issues or client evaluation occurs, please open a new issue.

Note, however, multidimensional arrays (this issue) aren't supported at all as well as single-dimensional ones.