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D

data integrity
The quality of a database that exhibits entity and referential integrity, and has controls to ensure no values in any of the fields lie outside their expected range. Often it implies that the database is reconcilable to other databases.

DTD
Document Type Definition. A DTD defines the legal building blocks of an XML document. It defines the document structure with a list of legal elements.

EJB
Enterprise Java Beans. An architecture for setting up program components, written tin the Java language, that run in the server parts of a computer network that uses the client-server model.

entity
Something about which you want to store data; typically a person, place, thing, concept, or event.  Also called a record in the old file-based system.   Entities are grouped together to form tables or entity sets

entity integrity
The absence of null values in a primary key. Guarantees that each entity will have a unique identity. See also referential integrity.

FIX messaging protocol
Financial Information eXchange (FIX) protocol is a messaging standard developed specifically for the real-time electronic exchange of securities transactions. FIX is a public-domain specification owned and maintained by FIX Protocol, Ltd.

foreign key

An attribute in one table that is used to relate that data to data in another table. Example: a student table may contain an attribute called class code. In the student table the class code is a foreign key because it allows us to relate that table to the class table where the class code is the primary key and contains the class year. We could then print a list of students and their class standing as a result of this foreign key/primary key relationship.