PostgreSQL

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

MySQL, SQL server, and Oracle.

Question 2

What are some advantages of learning a relational database?

Answer 2

categorizing data, accuracy, ease of use, collaboration, security.

Question 3

What is one way to see if PostgreSQL is running?

Answer 3

sudo service postgresql status

Question 4

What is a database schema?

Answer 4

a collection of tables.

Question 5

What is a table?

Answer 5

objects that contain all data in a database.

Question 6

What is a row?

Answer 6

a single group of related content within a table.

Question 7

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

Answer 7

SQL is where you learn how to work with a database. JavaScript is a full on programming language that is later leveraged to help you write server-sided code.

Question 8

How do you retrieve specific columns from a database table?

Answer 8

select “column name”

Question 9

How do you filter rows based on some specific criteria?

Answer 9

where “column name” = ‘specific name

Question 10

What are the benefits of formatting your SQL?

Answer 10

readability and consistent style.

Question 11

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

Answer 11

=, <, >, or

Question 12

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

Answer 12

limit number;

Question 13

How do you retrieve all column from a database table?

Answer 13

select *

Question 14

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

Answer 14

desc = descending or asc = ascending

Question 15

How do you add a row to a SQL table?

Answer 15

insert statement

Question 16

What is a tuple?

Answer 16

internal representation of a row in a table in PostGreSQL

Question 17

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

Answer 17

select property=’string’ property=’string’

Question 18

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

Answer 18

returning *;

Question 19

How do you update rows in a database table?

Answer 19

insert into

Question 20

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

Answer 20

So you don’t update everything.

Question 21

How do you delete rows from a database table?

Answer 21

delete command

Question 22

How do you accidentally delete all rows from a table?

Answer 22

if you don’t include a where clause.

Question 23

What is a foreign key?

Answer 23

a column in a table that points to a primary key or unique key column in the same or another table.

Question 24

How do you join two SQL tables?

Answer 24

using the join keyword.

Question 25

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

Answer 25

as

Question 26

What are some examples of aggregate functions?

Answer 26

sum(), avg(), count()

Question 27

What is the purpose of a group by clause?

Answer 27

group two tables together.