Unit 9 - database structure

Question 1

Flat-file database

Answer 1

Also known as a single-table databse, made up of a single table. Structured, persistent collection of data.

Question 2

Fields

Answer 2

The columns of a database; each field has its own defined data type. Contains particular piece of information/property about an entity.

Question 3

Record

Answer 3

Rows in a database (exluding name of fields/column headings). Group of fields related to a particular entity.

Question 4

Entity

Answer 4

Anything about which data is collected & stored.

Question 5

5 data types in databases

Answer 5

Real - data that has a decimal point
Character - single letter/text value
Integer - whole number
Text/alphanumeric - string of characters
Boolean - True or False
Date/Time - values that represent data and/or time in specified format

Question 6

Primary key

Answer 6

A field that uniquely indentifies a single record from all the others in a database table. Never repeat.

Question 7

SQL

Answer 7

Strutured querry language; standard language for manipulating database

Question 8

State 4 different SQL selection statements + meaning

Answer 8

SELECT - picks field(s) you want to view from database.
FROM - shows which database/table information is taken from
WHERE - specifies condition for retrieved data, e.g. parameters for another field. Can use equal to, less than, etc. and boolean operations.
* - selects all fields in database table

Question 9

State 3 different SQL sorting statements & arithmetic operations + meaning

Answer 9

ORDER BY [field] [keyword] - sorts the fields/data retrieved from a table in ascending/descending order. Keyword will be ASC or DESC
Sum - sums all numeric values in field. E.g. SELECT Sum(Field name)
Count - counts number of records (that meet specific criteria). E.g. SELECT Count(Field name)

Question 10

How should SQL statements be ended?

Answer 10

With colon ; to mark end of statement