CheckIndexCanBeKey checks whether an Index can be a Key in schema.

CheckMaxOneRowCond check if a condition is the form of (uniqueKey = constant) or (uniqueKey = Correlated column), it returns at most one row.

ResolveColumnAndReplace replaces columns fields of expressions by children logical plans.

ResolveExprAndReplace replaces columns fields of expressions by children logical plans.

BuildKeyInfoPortal is a hook for other packages to build key info for logical plan.

SetPredicatePushDownFlag is a hook for other packages to set rule flag.