The present invention specifies database security at a row level and, optionally, at a column and table level. The systems and methods cluster one or more sets of rows with similar security characteristics and treat them as a named expression, wherein clustered data is accessed based on associated row-level security. The systems and methods specify a syntax that invokes row(s), column(s) and/or table(s) security via programming statements. Such statements include arbitrary Boolean expressions (predicates) defined over, but not restricted to table columns and/or other contextual data. These statements typically are associated with query initiators, incorporated into queries therefrom, and utilized while querying data. Rows of data that return "true" when evaluated against an aggregate of associated security expressions are said to "satisfy" the security expressions and enable access to the data stored therein. Such security expressions can be created and invoked via the Structured Query Language (SQL) database programming language.