1. In a computing environment, a method of facilitating mapping of data between object oriented programs and database storage tables, the method comprising: receiving user input from a user, wherein the user input comprises a plurality of parts, wherein each part comprises: a specification of a source, wherein the specification of a source comprises specification of at least one of a hierarchy type, a single type, a multiple type, or an association type, wherein a hierarchy type indicates that a part applies to all entities that are instances of the given type or some type derived from the given type, further wherein a hierarchy type makes available a single range variable of the indicated type; and wherein a single type indicates that a part applies to all entities that are specifically instances of the given type, not derived from the given type, further wherein, a single type makes available a single range variable of the indicated type, further wherein a multiple type indicates that the part applies to all entities implementing one of a set of types, and wherein a multiple type makes available a single range variable that is a most derived common ancestor for all of the types specified, further wherein an association type indicates that a part applies to a given relationship, and wherein an association type makes available two range variables, one for each side of a relationship; and a projection, wherein each projection assigns values to table columns including zero or more assignments, each assignment comprising a column name and a value, where the value follows one of the following patterns: a value literal, a property chain, a navigation key, wherein a value literal indicates that for a given source and optional filter, a specified column has a given constant value, further wherein a property chain is a member access chain where a leaf is an entity or range variable, intermediate members are complex properties and ending with a primitive property, further wherein a navigation key is a member access chain comprising a navigation property on a range variable and a key property of a related end; and based on the plurality of parts received, generating one or more views, wherein the one or more views describe relationships between model extents and database tables.