S7 Relational Databases and SQL

Question 1

What is a database?

Answer 1

A way of holding data in an organised way so that it is quick and and easy to find a particular item, or all the items meeting a certain criteria. It contains one or more tables.

Question 2

What sections does a table have?

Answer 2

rows, records, fields, columns

Question 3

What is a primary key

Answer 3

A unique identifier (no 2 records will have the same)

Question 4

What happens in a relational database?

Answer 4

Each entity has its own table, and the tables are linked by a common field

Question 5

What are the advantages of using a relational database?

Answer 5

Elimination of data inconsistency and data redundancy.

Question 6

What is a foreign key?

Answer 6

A field which is a primary key in a linked table.

Question 7

What are the 3 possible relationships between tables?

Answer 7

One-to-one, one-to-many, many-to-many

Question 8

What is SQL used for?

Answer 8

Querying and updating tables in a relational database.

Question 9

What is the syntax for a SELECT statement?

Answer 9

SELECT list, of, fields, to, be, displayed
FROM list the table/s where the data will come from
WHERE list = “of search criteria”
ORDER BY order of results default = ascending

Question 10

How are dates portrayed in SQL

Answer 10

BETWEEN #01/01/2019# AND #31/12/2019#

Question 11

What phrase do you need to use when querying 2 tables?

Answer 11

WHERE (Table1. Primary key = Table2. foriegn key)

Question 12

What syntax is used for a INSERT INTO statement?

Answer 12

INSERT INTO tableName (column1, column2,…)
VALUES (value1, value 2,…)

NOTE: If all the fields are being added in the correct order, it is not necessary to specify the field names.

Question 13

What syntax is used for an UPDATE statement?

Answer 13

UPDATE tableName
SET column1 = value1, column2 = value2,…
WHERE column = value

Question 14

What syntax is used for a DELETE statement?

Answer 14

DELETE FROM tableName
WHERE column = value