Postgres DBMS

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

Opensource database. MySQL, SQLite, Sql Server, Oracle

Question 2

What are some advantages of learning a relational database?

Answer 2

Commonly used

Question 3

What is one way to see if PostgreSQL is running?

Answer 3

top, psql

Question 4

What is a database schema?

Answer 4

Definition of database tables and relations

Question 5

What is a table?

Answer 5

List of tabular data with columns defining the data

Question 6

What is a row?

Answer 6

One set of data in the table

Question 7

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

Answer 7

SQL is a language to communicate with a relational database server. It’s a declarative language where you state your intent and the server figures out what you want.

Question 8

How do you retrieve specific columns from a database table?

Answer 8

select

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

easier to read

Question 11

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

Answer 11

, =, !=

Question 12

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

Answer 12

limit clause

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

Question 15

How do you add a row to a SQL table?

Answer 15

insert

Question 16

What is a tuple?

Answer 16

a finite ordered list of elements

Question 17

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

Answer 17

add multiple values 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 *

Question 19

How do you update rows in a database table?

Answer 19

update (header) (tuples) where clause

Question 20

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

Answer 20

to select specific rows

Question 21

How do you delete rows from a database table?

Answer 21

delete from

Question 22

How do you accidentally delete all rows from a table?

Answer 22

if you don’t set a where clause

Question 23

What is a foreign key?

Answer 23

key in a different table

Question 24

How do you join two SQL tables?

Answer 24

join

Question 25

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

Answer 25

Use an alias as

Question 26

What are some examples of aggregate functions?

Answer 26

sum, avg, min, max, count

Question 27

What is the purpose of a group by clause?

Answer 27

group results by a values of a column