If some cardinality ratio or dependency cannot be determined from the requirements, the users must be questioned further to determine these structural constraints
DBMS typically includes a database security and authorization subsystem that is responsible for ensuring the security of portions of a database against unauthorized access
we discuss differences between specialization/generalization lattices (multiple inheritance) and hierarchies (single inheritance), and elaborate on the differences between the specialization and generalization processes during conceptual database schema design. We discuss constraints that apply ...
A database schema, along with primary key and foreign key dependencies, can be depicted by schema diagrams.
This chapter discusses techniques for securing databases against a variety of threats. It also presents schemes of providing access privileges to authorized users.
Entity types that do not have key attributes of their own are called weak entity types. In contrast,regular entity types that do have a key attribute—which include all the examples discussed so far—are called strong entity types
Object databases is the power they give the designer to specify both the structure of complex objects and the operations that can be applied to these objects
IBM developed the original version of SQL, originally called Sequel, as part of the System R project in the early 1970s.
The company is organized into departments. Each department has a unique name, a unique number, and a particular employee who manages the department. We keep track of the start date when that employee began managing the department. A department may have several locations. A department controls a nu...
Self-describing nature of a database system Insulation between programs and data, and data abstraction Support of multiple views of the data Sharing of data and multiuser transaction processing
The natural join operation operates on two relations and produces a relation as the result.