1. A computer-implemented method, comprising: detecting an access statement that seeks access to a row in a database table for which row level security is active; creating a predicate for the access statement, where the predicate is based, at least in part, on an access control expression associated with the row, where the access control expression depends, at least in part, on an instance of an expression data type associated with the row; populating an attribute of the predicate with a value acquired from one of, a context associated with the entity that provided the access statement, an environment from which the access statement was provided, and a context associated with the access statement; computing a predicate value; and selectively providing access to the row based, at least in part, on the predicate value.