DATABASE Flashcards
Raw Facts
Data
Result of processing raw data to reveal meaning
Information
Must be formatted for storage, processing, and presentation.
Raw Data
Are the foundation of information, which is the bedrock of knowledge.
Data
Shares, integrated computer structure that stores a collection of end user data and metadata.
Database
Raw facts of interest to end user.
End-user data
Data about data.
It provides description of data characteristics and relationships in data.
Complements and expands value of data.
Metadata
What does DBMS stands for?
Database Management System
It lets you create a database.
‘Add, change, delete, sort, and view the data in a database.
DBMS
When and where did DBMS created?
1990’s Sweden
Software whose source code is freely and publicly available.
Open source software
Is a free and open-source cross-platform web server solution package developed by Apache Friends.
XAMPP
XAMPP stands for
X-operating system, Apache, Mysql, Php, Perl
Consisting mainly of the Apache HTTP Server, MariaDB database, and interpreters for scripts written in the PHP and Perl programming languages.
XAMPP
View data logically rather than physically
Relational model
Structural and data independence
Resembles a file conceptually
Table
Is easier to understand than hierarchical and network models
Relational database model
Perceived as a two-dimensional structure composed of rows and columns
Table
Represents a single entity occurrence within the entity set.
Table row
Represents an attribute, and each column has a distinct name.
Table column
TRUE or FALSE
Each intersection of a row and column represents a single data value.
TRUE
TRUE or FALSE
All values in a column must conform to the same data format.
TRUE
Each column has a specific range of values known as the
Attribute Domain
TRUE or FALSE
The order of the rows and columns is important to the DBMS.
FALSE
The order of the rows and columns is immaterial to the DBMS.
TRUE or FALSE
Each table must have an attribute or combination of attributes that uniquely identifies each row.
TRUE
Provides detailed accounting of all tables found within the user/designer-created database
Contains (at least) all the attribute names and characteristics for each table in the system
Contains metadata: data about data
Data dictionary
Contains metadata
Detailed system data dictionary that describes all objects within the database
System catalog
process of determining the particular tables and columns that will comprise a database.
Database Design
(like a noun): person, place, thing or event
Entity
(like an adjective or adverb): property of an entity
Attribute
association between entities
Relationship
Relational modeling ideal
Should be the norm in any relational database design
1:M relationship
Should be rare in any relational database design
1:1 relationship
Cannot be implemented as such in the relational model
can be changed into 1:M relationships
M:N relationships
Popular and widely used language for retrieving and manipulating database data
Structured Query Language (SQL)
When did SEQUEL renamed?
1980
Used by most DBMSs
Structured Query Language (SQL)
When did sql developed
mid-1970s
question represented in a way that the DBMS
can understand
Query
TRUE or FALSE
There is a special formatting rules in SQL
FALSE
No special formatting rules
Use this command to retrieve specified columns
and all rows; e.g., list the number, name and balance
of all customers
SELECT
It indicate all columns in the
SELECT clause
asterisk (*)
Used to retrieve rows that satisfy some condition
WHERE clause
column name, comparison
operator followed by either a column name or a value
Simple condition
Connects two or more simple
conditions with AND, OR, and NOT operators
Compound condition
all simple conditions are true
AND operator
any simple condition is true
OR operator
Reverses the truth of the original
condition
NOT operator
Use instead of AND operator
Use when searching a range of values
Makes SELECT commands simpler to construct
BETWEEN Operator
Does not exist in the database
but is computed using data in existing columns
Computed column
Used for pattern matching
LIKE Operator
Represents any single character
Underscore (_)
TRUE or FALSE
By default, no defined order in which results are displayed
TRUE
list data in a specific
order
ORDER BY clause
column on which data is to be
sorted
Sort key or key
Is default sort order
Ascending
For descending order sort, use ___________
DESC
Used to calculate totals of columns
SUM Function
Eliminates duplicate values
Used with COUNT function
DISTINCT Operator
an inner query placed inside another
query
Subquery
uses subquery results
Outer query
creates groups of rows that share
common characteristics
Grouping
What is the difference between HAVING and WHERE.
WHERE: limit rows
HAVING: limit groups
Can use together if condition involves both rows and
groups
