PostgresSQL

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

MySQL, SQLite & MariaDB

Question 2

What are some advantages of learning a relational database?

Answer 2

Relational databases are arguably the most widely used kind of database. SQLite is an embedded relational database that is deployed in a staggeringly high number of devices and applications

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

Question 5

What is a table?

Answer 5

list of row with the same attribute

Question 6

What is a row?

Answer 6

set of

Question 7

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

Answer 7

SQL is declarerity programming language

Question 8

How do you retrieve specific columns from a database table?

Answer 8

a

Question 9

How do you filter rows based on some specific criteria?

Answer 9

where

Question 10

What are the benefits of formatting your SQL?

Answer 10

a

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 clous

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 into table name “content” values ‘value’

Question 16

What is a tuple?

Answer 16

a list of values is referred to as a tuple.

Question 17

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

Answer 17

insert into “products” (“name”, “description”, “price”, “category”)
values (‘Ostrich Pillow’, ‘Feel comfy and cozy!’, 99, ‘self care’),
(‘Tater Mitts’, ‘Scrub some taters!’, 6, ‘cooking’)

Question 18

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

Answer 18

returing keyword

Question 19

How do you update rows in a database table?

Answer 19

update tablename set “attributename”=’value’ where “attribute”=”value”

Question 20

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

Answer 20

or else it will delete whole table

Question 21

How do you delete rows from a database table?

Answer 21

DELETE FROM table_name WHERE condition;

Question 22

How do you accidentally delete all rows from a table?

Answer 22

delete from “tablename”;

Question 23

What is a foreign key?

Answer 23

share attribute between 2 tables

Question 24

How do you join two SQL tables?

Answer 24

join “tablename” using “columnname”

Question 25

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

Answer 25

using as keyword

Question 26

What are the three states a Promise can be in?

Answer 26

pending: initial state, neither fulfilled nor rejected.
fulfilled: meaning that the operation was completed successfully.
rejected: meaning that the operation failed.

Question 27

How do you handle the fulfillment of a Promise?

Answer 27

promise.then()

Question 28

How do you handle the rejection of a Promise?

Answer 28

promise.catch()