D426 WGU Notes
Database application - ✅✅-software that helps business users interact with
database systems
Database administrator - ✅✅ -responsible for securing the database system
against unauthorized users, enforces procedures
Authorization - ✅✅-limits user access
Rules - ✅✅ -database systems ensure data is consistent with structural and
business rules
Query processor - ✅✅ -interprets queries, creates plan to modify database/retrieve
data, and returns query results
Query optimization - ✅✅ -performed by query processor to ensure most efficient
instructions are executed
Indexes - ✅✅-quickly locate data
transaction manager - ✅✅-ensures transactions are properly executed, prevents
conflicts between concurrent transactions, restores database to consistent state
INSERT -✅✅-insert rows into a table
SELECT - ✅✅-retrieves data from a table
UPDATE - ✅✅-modifies existing rows in a table
- Uses SET clause for new column values
- Uses WHERE clause for which rows to update, or updates all rows
DELETE - ✅✅ -deletes rows from a table
- FROM follows table name
- Use WHERE for which rows to delete, or delete all rows
CREATE TABLE - ✅✅-creates new table by specifying the table and column
names, and column data types
✅✅-stores integer values
INT (data type) -
DECIMAL (data type)(M,D) - ✅✅-stores fractional numeric values; numerical with
M digits, D digits is decimal point
, VARCHAR (data type) -✅✅-stores textual values, values with 0 to N characters
DATE (data type) - ✅✅-stores year/month/day data
Analysis Phase - ✅✅-specifies database requirements without regard to specific
database system
What are requirements represented by? - ✅✅-Entities, relationships, and attributes
Entity -✅✅-person, place, activity, or thing
Relationship - ✅✅-link between entities
Attribute - ✅✅-descriptive property of an entity
Other names for analysis? - ✅✅-Conceptual deisng, entity-relationship modeling,
requirements definition
Logical Design - ✅✅-- Phase that implements database requirements in a specific
database system
Logical Design in Relational Database Systems - ✅✅ -Converts entities,
relationships, and attributes into tables, keys, and columns
Physical Design Phase - ✅✅ -Adds indexes and specifies how tables are organized
on storage media, affects processing speed
Data Independence - ✅✅-Principle that Physical Design never affects query
results
MySQL Command-Line Client - ✅✅ -text interface in MySQL Server, returns an
error code and description if syntactically incorrect/database can't execute
Tuple - ✅✅-ordered collection of elements closed in parentheses
Table - ✅✅-has a name, fixed tuple of columns, and varying set of rows
Column - ✅✅-name and data type
Row - ✅✅-unnamed tuple of values, each value corresponds to a column and
belongs to the column's data type
Data type - ✅✅-named set of values from which column values are drawn
Database application - ✅✅-software that helps business users interact with
database systems
Database administrator - ✅✅ -responsible for securing the database system
against unauthorized users, enforces procedures
Authorization - ✅✅-limits user access
Rules - ✅✅ -database systems ensure data is consistent with structural and
business rules
Query processor - ✅✅ -interprets queries, creates plan to modify database/retrieve
data, and returns query results
Query optimization - ✅✅ -performed by query processor to ensure most efficient
instructions are executed
Indexes - ✅✅-quickly locate data
transaction manager - ✅✅-ensures transactions are properly executed, prevents
conflicts between concurrent transactions, restores database to consistent state
INSERT -✅✅-insert rows into a table
SELECT - ✅✅-retrieves data from a table
UPDATE - ✅✅-modifies existing rows in a table
- Uses SET clause for new column values
- Uses WHERE clause for which rows to update, or updates all rows
DELETE - ✅✅ -deletes rows from a table
- FROM follows table name
- Use WHERE for which rows to delete, or delete all rows
CREATE TABLE - ✅✅-creates new table by specifying the table and column
names, and column data types
✅✅-stores integer values
INT (data type) -
DECIMAL (data type)(M,D) - ✅✅-stores fractional numeric values; numerical with
M digits, D digits is decimal point
, VARCHAR (data type) -✅✅-stores textual values, values with 0 to N characters
DATE (data type) - ✅✅-stores year/month/day data
Analysis Phase - ✅✅-specifies database requirements without regard to specific
database system
What are requirements represented by? - ✅✅-Entities, relationships, and attributes
Entity -✅✅-person, place, activity, or thing
Relationship - ✅✅-link between entities
Attribute - ✅✅-descriptive property of an entity
Other names for analysis? - ✅✅-Conceptual deisng, entity-relationship modeling,
requirements definition
Logical Design - ✅✅-- Phase that implements database requirements in a specific
database system
Logical Design in Relational Database Systems - ✅✅ -Converts entities,
relationships, and attributes into tables, keys, and columns
Physical Design Phase - ✅✅ -Adds indexes and specifies how tables are organized
on storage media, affects processing speed
Data Independence - ✅✅-Principle that Physical Design never affects query
results
MySQL Command-Line Client - ✅✅ -text interface in MySQL Server, returns an
error code and description if syntactically incorrect/database can't execute
Tuple - ✅✅-ordered collection of elements closed in parentheses
Table - ✅✅-has a name, fixed tuple of columns, and varying set of rows
Column - ✅✅-name and data type
Row - ✅✅-unnamed tuple of values, each value corresponds to a column and
belongs to the column's data type
Data type - ✅✅-named set of values from which column values are drawn
