Documentation

Return an error if the schema is not isomorphic to the base database context. A schema is fully isomorphic iff all relvars in the base context are in the "out" relvars, but only once. TODO: add relvar must appear exactly once constraint

Relation variables names represented in the virtual schema space. Useful for determining if a relvar name is valid in the schema.

Check that all mentioned relvars are actually present in the current schema.

If the database context expression adds or removes a relvar, we need to update the isomorphs to create a passthrough Isomorph.

Morph a relational expression in one schema to another isomorphic schema. Returns a function which can be used to morph a GraphRefRelationalExpr. Here, we naively apply the morphs in the current context ignoring past contexts because: * the current schema may not exist in past * this function should only be used for showing DDL, not for expression evaluation. * if a schema were renamed, then the path to past isomorphisms in the transaction graph tree would be lost.

Apply the isomorphism transformations to the relational expression to convert the relational expression from operating on one schema to a disparate, isomorphic schema.

Show metadata about the relation variables in the isomorphic schema.

Create inclusion dependencies mainly for IsoRestrict because the predicate should hold in the base schema.

Apply SchemaIsomorphs to database context data.