postgresSQL

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

powerful open source Relational Database Management System. Some alternative relational databases are (MySQL, SQL Server, and Oracle by Oracle Corporation)

Question 2

What are some advantages of learning a relational database?

Answer 2

if you are storing related data. They can store and modify data in a way that makes data corruption as unlikely as possible. (retrieve and store data quickly)(they are very widely used)

Question 3

What is one way to see if PostgreSQL is running?

Answer 3

with the top command

Question 4

What is a database schema?

Answer 4

a collection of tables and defines how the data in a relational database should be organized

Question 5

What is a table?

Answer 5

where data is stored in relations. They are a list of rows each having the same set of attributes

Question 6

What is a row?

Answer 6

represents a single implicitly structured data item in a table(set of attributes with information)

Question 7

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

Answer 7

Structured Query Language is the primary way of interacting with relational database. It is a powerful way of retrieving, creating, and manipulating data in a relational database.

Question 8

How do you retrieve specific columns from a database table?

Answer 8

with the select keyword, double quotes, and comma to separate them

Question 9

How do you filter rows based on some specific criteria?

Answer 9

with the where clause

Question 10

What are the benefits of formatting your SQL?

Answer 10

provides us with the ability to limit the number of rows included in a result set. For readability

Question 11

How do you retrieve all columns from a database table?

Answer 11

with an asterisk *

Question 12

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

Answer 12

with an order by clause

Question 13

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

Answer 13

with the limit keyword

Question 14

How do you add a row to a SQL table?

Answer 14

execute the command of insert into, and then values

Question 15

What is a tuple?

Answer 15

a list of values

Question 16

What is a tuple?

Answer 16

an ordered list of values

Question 17

How do you update rows in a database?

Answer 17

with the update key and the where clause

Question 18

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

Answer 18

with the “returning” clause

Question 19

How do you update rows in a database?

Answer 19

with the “update” key and column name equal the value

Question 20

How do you accidentally delete all rows from a table?

Answer 20

if you delete from “the name of the table” and thats alll you put in

Question 21

How do you delete rows from a database table?

Answer 21

with the “delete from” keyword

Question 22

What is a foreign key?

Answer 22

when a column refers to values in a column from a different table. There is just one column that links the tables together

Question 23

How do you join two SQL tables?

Answer 23

with a join clause

Question 24

How do you join two SQL tables?

Answer 24

with a “join” clause and the “using” clause. Then have the identifier inside a parenthesis

Question 25

What are some examples of aggregate functions?

Answer 25

max( ), avg( ), count( ), min( ), sum( ), every( )

Question 26

What is the purpose of a group by clause?

Answer 26

if you want to separate rows into groups and perform aggregate functions on those groups of rows only