CS 2203 Unit 1 – 8 Self Quiz Review Questions
The main purpose of the information model is to inform software developers and provide protocol-specific constructs.
Which term describes each two-dimensional table or file in the relational model?
b. Relational Database
c. Data Warehouse
d. None of the Above
If a relation has more than one candidate key the one chosen to represent the relation is called the:
a. primary key
b. foreign key
c. alternate key
d. candidate key
The first hierarchial DBMS was ____ and was released by IBM in 1968?
a. IMS (Information Management System)
d. …show more content…
list all those who are resident and all those who have one child
b. list all those with 1 child
c. list all those who are resident
d. list only those who have one child as well as all those who are resident
In strict relational terminology, an attribute is
a. a table
b. a field
c. an entity
d. a record
The entity integrity constraint says that if a relation R2 includes a foreign key FK matching the primary key PK of other relation R1, then every value of FK in R2 must either be equal to the value of PK in some tuple of R1 or be wholly null.
The primary key does not have to be unique in relations that have a one to many relationship.
A foreign key can accept a null value unless otherwise restricted by a null constraint.
Integrity constraints are rules that help ensure the
Click here to unlock this and over one million essaysGet Access
* As explained throughout this course, entity relationship modeling is a critical element of database design. If the database is not properly modeled, it is unlikely that the database will be properly developed. Using this knowledge, explain the key reasons why entity relationship modeling is important, and determine at least (1) way in which it impacts the overall development of the database.
A relational database is a database that consists of a collection of tables with columns showing entities, and rows showing data. This type of database uses a primary key and foreign key. The foreign key in another table will point to the primary key of a table, and this is how tables can relate to each other. This permits for one-to-one, one-to-many, and many-to-many relationship between the data. An advantage of relational databases includes the ease of adding or modifying new tables and entities without needing to change the structure of the database already in place. Relational database have many features, including indexing, setting data type, and setting validation tests, all these help to ensure data integrity.
If we consider an example of a database for billing the claims to the provider, we have two tables in the database as ‘Claims’ and ‘Provider’. ‘Claims’ have the claim information such as (ClaimNumber, ClaimType, Type of service, Admission details) and ‘Provider’ have the provider information such as (ProviderID, FederalTaxID, NPI, PointOfService). The primary keys for ‘Claims’ is “ClaimNumber” and for ‘Provider’ is “ProviderID”.
The example discussed above on Customers table and Orders table is a one-to-many relationship. As each customer places multiple orders, each order only belongs to one customer. When creating a relationship between two tables, if only one of the related fields is unique, a one-to-many relationship is automatically set.
To enforce referential integrity for this relationship, select the Enforce Referential Integrity check box. Click Create. Access draws a relationship line between the two tables. If you selected the Enforce Referential Integrity check box, the line appears