Chapter 7 Flashcards
Database fundamentals
What is data persistence?
Data is permanently available.
A user is granted permission to access a database. What is this an example of?
Data definition
What type of database stores images?
Non relational database (dbms)
Is document database is what type of database?
Non relational database
Pictures with meta data are classified ad what type of data?
Semi-structured data
What are csv files used for?
Reporting
What dimension is a flat file?
2 dimensions
What would drive the need to use Database?
Multiple users Scalability Speed Holding variety of data Number of records Data persistence
What happens when a user tries to write to a flat file?
The file is locked
How can speed be increased when using databases?
By placing the database and their log file on SSD rather than HDD
True or false
With databases all changes are saved after each cell of data is edited
True
Is Relational database an example of structured data?
Yes
How does RDBMS ensure data integrity?
No duplicated rows
Null values used when there is no data
Column values must not be repeating
What does a null value mean?
The absence of data
What is a schema?
Rules and structure of a database.
What are the 2 types of schema in relational database?
Logical schema
Physical schema
Which should exist first? The logical schema or the physical schema?
Logical schema
What does the schema define?
Tables Forms Reports Queries data type allowed Macro and module
What is a row in a table?
Record
What are the columns in a table called?
Fields
What makes a table in a database relational?
It must be a primary key
Who places constraints on fields?
The database administrator
What do macro and modules do for databases?
Let you add functionalities to a database, for example a set time to run a report
Which database stores values as blobs?
Key/value database
What are the ways that database can be accessed?
Manual Access
Direct Access
Programmatic Access
User interface and utility access
What is manual access?
Going directly into the table
What happens with direct access
Access the database table across a network. Usually done with an API(application programming interface) or ODBC(open database connection, JDBC(Java database connection)
What is the other name for permission?
Privileges
What are the 3 different types of permissions?
Server permission
Database permission
Object permission
What is the ALTER command used for in SQL
Add
Delete
Modify columns
ALTER TABLE table_name ADD columb_name datatype;
DROP
What is the CREATE command used for in database management?
Create tables in a database
CREATE TABLE table_name (column datatype, column2 datatype)
What command is used to delete a table or database?
DROP TABLE table_name;
How is the UPDATE command used?
UPDATE Column name
SET field=xxxxx
WHERE field=
What are the 2 recommended ways to backup a database
Database Data dump
Run a backup
Where are flat files stored
On the RAM
