WGU exam with complete solutions
2024/2025
Data
numeric , textual , visual or audio information that describes real-world systems.
varies in ways such as scope, format, access.
analog data
Historically most common before computers, encoded as continuous variations
on various physical media.
digital data
most common today, recorded as 0's and 1's on electronic and magnetic media.
database designer
determines the format of each data element and the overall database structure
database user
a consumer of data in a database. can either use an application or submit queries
directly to the database. they use, request and update data. to generate reports
transaction
a group of queries that must be completed or rejected as whole. will result in
incomplete or incorrect data if not terminated as a whole.
Query processor
interprets queries, creates a plan to modify the database or retrieve data, and
returns query results to the application.
Query optimization
to ensure the most efficient instructions are executed on the data from the
processor.
Storage Manager
translates the query processor instructions into low-level file-system commands
that modify or retrieve data.
indexes
, used by the storage manager to quickly locate data
catalog
also called a data dictionary , a directory of tables, columns and indexes as well
as other database objects.
relational database
a database that stores data in tables that consist of rows and columns, similar to
a spreadsheet
SQL
Structured Query Language
NoSQL
A new generation of database management systems that is not based on the
traditional relational database model.
query
command for a database that typically inserts, retrieves, updates and deletes data
from the database.
crud
Create, Read, Update, Delete
statement
a database command such as a query that inserts , selects updates and deletes
data
SELECT
Retrieves data from a table
UPDATE
modifies data in a table
data type
indicates the type of data that can be stored in a field of a column
data independence
A condition in which data access is unaffected by changes in the physical data
storage characteristics.
database model
Describes the relationship between the data elements and provides a framework
for organizing the data. contains 3 parts
data structures
operations
rules
relational model
A database model that describes data in which all data elements are placed in
two-dimensional tables, called relations, which are the logical equivalent of files.
row