PostgreSQL

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

Postgres is an open source relational database. MySQL, Microsoft SQL, and Oracle

Question 2

What are some advantages of learning a relational database?

Answer 2

Web developers will use a database

Question 3

What is one way to see if PostgreSQL is running?

Answer 3

run sudo service postgreql start in one terminal and run top in another.

Question 4

What is a database schema?

Answer 4

A collect of tables that your data conforms to.

Question 5

What is a table?

Answer 5

A list of rows with the same attributes

Question 6

What is a row?

Answer 6

A single record in the database.

Question 7

What is SQL and how is it different from languages like JavaScript?

Answer 7

The language used to interact with relational databases. It is declarative.

Question 8

How do you retrieve specific columns from a database table?

Answer 8

select “blank” from “blank”

Question 9

How do you filter rows based on some specific criteria?

Answer 9

where clause

Question 10

What are the benefits of formatting your SQL?

Answer 10

Makes it easier to find certain rows or columns

Question 11

What are four comparison operators that can be used in a where clause?

Answer 11

equal, less than, greater than, not equal

Question 12

How do you limit the number of rows returned in a result set?

Answer 12

Limit clause followed by number

Question 13

How do you retrieve all columns from a database table?

Answer 13

select *

Question 14

How do you control the sort order of a result set?

Answer 14

Order by price - (auto ascending)

order by price “price” desc

Question 15

How do you add a row to a SQL table?

Answer 15

insert clause

into ‘table name’

Question 16

What is a tuple?

Answer 16

A list of values

Question 17

How do you add multiple rows to a SQL table at once?

Answer 17

Each set of value in parentheses separated by commas.

Question 18

How do you get back the row being inserted into a table without a separate select statement?

Answer 18

returning clause

Question 19

How do you update rows in a database table?

Answer 19

update clause ‘table name’

Question 20

Why is it important to include a where clause in your update statements?

Answer 20

to target a specific row

Question 21

How do you delete rows from a database table?

Answer 21

delete clause

Question 22

How do you accidentally delete all rows from a table?

Answer 22

delete from ‘table name’

no where clause

Question 23

What is a foreign key?

Answer 23

A column in one table that refers to values in another table.

Question 24

How do you join two SQL tables?

Answer 24

join clause “tableName” using (“columnName”)

Question 25

How do you temporarily rename columns or tables in a SQL statement?

Answer 25

“columnName”.”name” as “tempName”

Question 26

What are some examples of aggregate functions?

Answer 26

avg, count, sum, every

Question 27

What is the purpose of a group by clause?

Answer 27

Separate rows into groups