SQL Select Statement Capabilities Quiz

12 Questions

What is the smallest unit of data storage?

Oto

Which data processing method involves using a keyboard and typewriter?

Mechanical Method

What is a 'Byte' in terms of data?

A unit of data storage

What is the main purpose of SQL (Structured Query Language)?

Querying databases

What does the term 'Batch processing' refer to?

Gathering information for processing in groups

What is a Nibble in terms of data?

A 4 bit unit of data

What is a Field in a table?

A column in a table that contains data entries

Which SQL clause is used to filter records based on a specified condition?

Where

What does the term 'Projection' refer to in SQL?

Selecting a certain column or field from a table

In a relational database, what is the purpose of the 'null' value in a field?

It represents a field with no value

What is the role of Authentication in databases?

Verifying the identity of someone who wants to use data resources

What is the purpose of an Arithmetic Expression in databases?

Operating on one operand to perform calculations

Study Notes

Data Storage Units

BIT: the smallest unit of data storage
Nibble: a 4-bit unit of data, half of a byte
Byte: a unit of data equivalent to eight binary digits

Data Processing Cycle

Gathering information: origin and input
Data processing: encoding, input, processing, and output
Storing: saving or not storing the output

Data Accessing Methods

Manual Method: using pen and paper
Mechanical Method: using keyboard and typewriter
Electronic Method: data processing using computers

Data Processing Modes

Batch Processing: the most inexpensive and efficient method for large organizations
On-line Processing: transactions are entered directly into the computer and processed immediately

Data Validation

Checking for errors to minimize erroneous data
Data must conform to specific criteria before being processed

Database Concepts

SQL: Structured Query Language used to query all databases
RDBMS: Relational Database Management System that uses the concept of linking different tables

Database Components

Table: a collection of related data entries with rows and columns
Field: a column in a table designed to maintain specific information about every record
Record: an individual entry that exists in a table
Column: a vertical entity in a table that contains all related data
Null Value: a value in a field with no value
Constant: a something with a fixed value
Variable: something that may have a varying value over time

Database Security

Controlling Database Access: an important aspect of database security
DY: denies user action on the objects within the database
User: an account that can connect and access objects inside the database
Enema: a group of database objects such as tables, views, clusters, and packages

SQL Select Statement

Projection: selecting a certain column or field from a table
Selection: retrieving a subset of rows or records in a table
Joining: combining data from more columns or tables
Generating Report: using the SELECT statement to retrieve data from the database

SQL Statement Options

SELECT * FROM Tablename: retrieves all columns from a table
SELECT column1, column2, ... FROM tablename: retrieves specific columns from a table
ORDER BY: arranges data in either ascending or descending order
WHERE: represents the command that will create a condition to be satisfied
Arithmetic Expression: used to perform calculations
Unary Operator: operates on one operand, denoting positive or negative values