MIS 336 Final Exam (Ch 6 & 7)
Intersection Table
N:M strong entity relationship, holds primary keys of the two tables as foreign keys and this combination of keys serves as the composite primary key
Four properties that need to be specified for each table column
Null Status, Data Type, Default Value, and Data Constraints
ID-Dependent Entity
an entity whose identifier includes the identifier of another entity. All ID-dependent entities are weak (existence depends on the presence of another entity).
Many-to-many relationships are represented by ________.
an intersection table which has 1:N relationships with the two tables
Table
During database design, each entity is replaced by a __________
Code for Creating a View
CREATE VIEW [Alias] AS SELECT [Column Name(s)], FROM [Table Name];
Columns
During database design, each attribute of the entity become _____________ of the table.
TRUE/FALASE When creating a table in the relational database design from an entity in the extended E-R model, the attributes of the entity become the rows of the table.
FALSE
TRUE/FALSE A null value is an attribute value that has been set to zero.
FALSE
SQL statement for creating a surrogate key
IDENTITY (Starting_Value , Increment)
Primary Key
Identifier of the entity become the ___________________.
Many to Many relationships need to have an __________
Intersection Table
Recursive Relationship
Occurs when an entity type has a relationship to itself. Three types (1:1, 1:N, N:M)
A good primary key should be
Short, numeric, fixed
What is the limitation on SELECT statements used in SQL Views?
Statements may not contain an ORDER BY clause.
TRUE/FALSE A surrogate key is appropriate when the primary key of a table contains a lengthy text field.
TRUE
TRUE/FALSE The first step in the database design process is to create tables and columns from entities and attributes.
TRUE
TRUE/FALSE The ideal primary key is short, numeric, and fixed.
TRUE
A referential integrity constraint policy that insures that foreign key values in a table are correctly maintained when there is a change to the primary key value in the parent table is called ________.
cascading updates
CHAR (n)
data type for a fixed-length character string having a maximum length of (n).
VARCHAR (n)
data type for a variable-length character string having a maximum length of (n).
In many-to-many relationships in a relational database design, ________.
the keys of both tables are placed in a third table
When representing a one-to-many relationship in a relational database design, ________.
the parent is always on the one side of the one-to-many relationship
All intersection tables are ______________ and __________________
weak and ID-Dependent
When transforming an E-R data model into a relational database design, the key of the parent entity should be placed as part of the primary key into the child entity ________.
when the child entity is ID-dependent