Glossary - Database Design and Development: An Essential Guide for IT Professionals - page 707

Binary relationship. Relationship in which two object sets participate. This is the
most common form of relationship between object sets.
Binary search. Widely used search technique where the data values are sorted. The
search begins at the middle of the series of values and proceeds to the left or the
right from the middle based on the value being searched for.
Boyce-Codd normal form (BCNF). A relation or table is in BCNF if it is already
in the third normal form and no key attribute is functionally dependent on any
nonkey attribute.
Bitmapped indexing. Compact, high-speed indexing method. A bitmap is an
ordered series of bits, one bit for each distinct value of the indexed column.
B-tree (balanced tree). Arrangement of sorted data values in nodes forming an
inverted tree with the root node at the top and an equal number of branch nodes
on either side.
B-tree indexing. Common indexing technique used in most DBMSs based on a B-
tree. The search begins at the root node and proceeds through the branch nodes
on either side.
Buffer. Region of computer memory that holds data being transferred from one
area to another. Data from database tables are fetched into memory buffers.
Memory buffer management is crucial for system performance.
Business rules. Specifications based on business practices of an organization that
need to be incorporated in the logical data model.
Candidate key. A single attribute or a set of attributes that uniquely identifies an
instance of an object set or entity type and can be a candidate to be chosen as
the primary key.
Cardinality. Cardinality of the relationship between two object sets indicates how
many instances of the first object set may be related to how many of the second.
CASE (computer-aided software engineering). CASE tools or programs help
develop software applications. A set of CASE tools many include code genera-
tors, data modeling tools, analysis and design tools, and tools for documenting
and testing applications.
Centralized database. Database where all data is physically stored in one location.
Checkpointing. Procedure for automatically pausing database operations, commit-
ting completed transactions, and saving copies of the database at predetermined
points. Database recovery may start at the latest checkpoint.
Clustering. Method for improving database performance. Related records that are
likely to be accessed together are placed in the same data block.
CODASYL (Conference on Data Systems and Languages). Organization com-
posed of hardware vendors, software vendors, and user groups. Among other
efforts, famously known for the development of COBOL.
Committed transaction. Database transaction that has successfully completed all of
its operations.
Composite key. Primary key made up of more than one attribute.
Concatenated key. Same as Composite key . Primary key consisting of more than
one attribute.