A C1ExpressConnection component is used when it is necessary to combine several tables into a single data set. C1ExpressTable components are attached to a C1ExpressConnection component by setting their ConnectionComponent property. These tables share a common database connection and a common row cache (data set). They can share the same data, for instance, if two C1ExpressTable components represent the same database table, or if one of them is a composite table including a database table that is also used in the other. In this case, if they share the same connection, changing data in one of them will be reflected in all others that include the affected rows. Updating modified data to the database is done for all tables sharing the connection as a whole, in one transaction. This is why the Update method belongs to the C1ExpressConnection component.

Conversely, two or more standalone C1ExpressTable components, not attached to a common C1ExpressConnection, use separate database connections and have completely independent copies of data (row cache).