Section 1
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Second Normal Form (2NF)
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Date created
Mar 1, 2020
Cards (53)
Section 1
(50 cards)
Second Normal Form (2NF)
When it is in first normal form and no nonkey column is dependent on only a portion of the primary key
Database
Structure that contains different categories of information and the relationships between these categories .
MIN
Calculates the minimum value in a numeric range
AND
All of the simple conditions must be met in order for the compound conditions to be true
AVG
Calculates the average value in a numeric range
DELETE
Deletes rows
INSERT
Adds rows to a table
WHERE
Retrieve rows for a specific thing or number
Null
Special value to represent cases which an actual value is unknown, unavailable, or not applicable
Primary Key
Unique identifier for a table.
MAX
Calculates the maximum value in a numeric range
Entity
Like a noun, a person, place, thing, or event
One-To-Many Relationships
Ex. One sales rep is associated with many customers.
Functional Dependence
A simple idea
Compound condition
connecting two or more simple conditions, with the AND, OR, or NOT, operators.
ORDER BY
List data in a specific order
First Normal Form (1NF)
A table that does not contain a repeating group
VARCHAR(n)
Alternative to CHAR that stores a character string up to "n" characters long. Only occupies amount of characters used
NOT NULL
Command in which you indicate which columns cannot contain null values
NOT
reverses the truth of the original conditions
A table is
A collection of rows and columns
Simple condition
has the form column name, comparison operator, the either another column name or a value
Data Type
Type of data the column can contain as well as the max number of characters or digits the column can store
Restrictions placed on table and columns
-Names cannot exceed 30 characters -Names must start with a letter -Names can contain letters, numbers, and underscores -Names cannot contain spaces
BETWEEN
Lets you specify a range of values
Drop Table Command
Deletes a table
Computed Column
Does not exist in the database but can be computed using data in the existing columns
LIKE
Uses one or more wildcard characters to test for a pattern match
CHAR(n)
Stores a character string "n" characters long. Use: Columns containing letters, special characters, and numbers not used in calculations
A table column in common database terminology is also referred to as a(n):
Tuple
Asterisk (*)
Indicate that you mean all columns
COUNT
Counts the number of rows in the table
CREATE TABLE
List, columns, data types, and column length
DATE
Stores dates
INT
Store integers (numbers without a decimal part)
What acronym refers to all of the major functions that are implemented in relational database applications?
Create, Read, Update, Delete (CRUD)
Nonkey Column
A column that is not part of the primary key
DESCRIBE
Lists all the columns in a table and their properties
Attribute
Property of an entity. Such as, color, height, identification number, and office numbers.
Relationship
Association between entities.
Third Normal Form (3NF)
When a table is in second normal form and the only determinants it contains are candidate keys
SMALLINT
Store integers but the valid range is smaller
UPDATE
Changes a value in a table
OR
If any of the simple conditions is true then the compound condition will be true
Normalization
Identifying the potential problems and implementing the ways to correct them
Relation
Two-dimensional table in which entries in the table are single-valued, each column has a distinct name, all values in the column match the name, the order of the rows and columns is immaterial, and each row contains unique values.
Aggregate Functions
Calculate sums, averages, counts, maximum values, and minimum values
A relational database is:
A collection of data items organized as a set of formally-described tables from which data can be accessed
DECIMAL(p,q)
Stores a decimal number "p" digits long with "q" of the digits being decimal places to the right of the decimal point. {For example: (5,2) indicates a number with 3 places to the left and 2 places to the right}
Script File or Script
Text file
Section 2
(3 cards)