C170 Data Management – Applications, Top Exam Questions and answers. VERIFIED.

C170 Data Management – Applications, Top Exam Questions and answers. VERIFIED. A database model - -is a conceptual framework for database software The relational model - -is a database model based on mathematical principles, with three parts: 1. A data structure that prescribes how data is organized. 2. Operations that manipulate data structures. 3. Rules that govern valid relational data. A domain - -is a named set of possible database values, such as integers, dictionary words, or logical values TRUE and FALSE. A tuple - -is a finite sequence of values, each drawn from a fixed domain. Ex: (3, apple, TRUE) is a tuple drawn from domains (Integers, DictionaryWords, LogicalValues). A relation - -is a named set of tuples, all drawn from the same sequence of domains. an attribute - -Each attribute has a name that is unique within the relation. Since each tuple position has a domain, each attribute also has a domain. Relational tuples differ from mathematical tuples in one respect - -In mathematics, the order of tuple values is significant. Ex: The tuples (7, 2) and (2, 7) are different. In the relational model, the order of tuple values is not significant, since each value is associated with a different attribute name. The most commonly used terms in relational database - -Row, column, and table. Occasionally tuple, relation, attribute and record, file, field are also used. In the relational data structure, which components are named? - -Domain, relation, and attribute Relational operation - Select - -selects a subset of rows of a table. Relational operation - Project - -eliminates one or more columns of a table. Relational operation - Product - -lists all possible combinations of rows of two tables. Relational operation - Join - -a product operation followed by a select operation. Relational operation - Union - -combines two tables by selecting all rows of both tables.