[10.x] Get indexes of a table

[hafezdivandari]

This PR adds Schema::getIndexes() method to get indexes' info of the given table.

Usage

Just like Schema::getColumns() added on #48357, the new Schema::getIndexes()method is to inspect the tables' indexes.

Schema::getIndexes()

• name (string): Name of the index
• columns (string[]): Array of indexed columns
• type (?string): Index type.
  • SQLite: null
  • MySQL: btree, fulltext, hash, rtree, spatial
  • PostgreSQL: btree, hash, gist, spgist, gin, brin
  • SQL Server: heap, clustered, nonclustered, xml, spatial, clustered columnstore, nonclustered columnstore, nonclustered hash
• unique (boolean): Is unique index?
• primary (boolean): Is primary index?

[liamkeily]

Nice work. It would be great to have Schema::hasIndex as well, to go with Schema::hasColumn

[hafezdivandari]

@liamkeily thanks for your comment, I totally agree, but these PRs are quite large and I don't want to add too many methods at once, that makes the PR difficult to review. Helper functions like Schema::hasIndex can easily be implemented later.