postsqul

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

PostgreSQL is a relational database system. other alternatives are MySQL, SQL Server by Microsoft, and oracle by Oracle Corporation.

Question 2

What are some advantages of learning a relational database?

Answer 2

be able to make logical connections and make tables

Question 3

What is one way to see if PostgreSQL is running?

Answer 3

by using the command sudo service PostgreSQL status

Question 4

What is a database schema?

Answer 4

collection of tables

Question 5

What is a table?

Answer 5

A table is an arrangement of information or data, typically in rows and columns

Question 6

What is a row?

Answer 6

represents a single, implicitly structured data item in a table

Question 7

How do you retrieve specific columns from a database table?

Answer 7

by using the select keyword

Question 8

How do you filter rows based on some specific criteria?

Answer 8

by using the where keyword

Question 9

What are the benefits of formatting your SQL?

Answer 9

it makes it easier to catch mistakes and read

Question 10

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

Answer 10

equal, less than and greater than, and not equal

Question 11

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

Answer 11

use the limit keyword

Question 12

How do you retrieve all columns from a database table?

Answer 12

by using the astric selector

Question 13

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

Answer 13

by using the order by

Question 14

How do you add a row to a SQL table?

Answer 14

by using the insert statement

Question 15

What is a tuple?

Answer 15

list of values

Question 16

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

Answer 16

by inputting values then use comma to input another

Question 17

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

Answer 17

use the returning keyword

Question 18

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

Answer 18

by using the update keyword

Question 19

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

Answer 19

to specify what row we are updating

Question 20

How do you delete rows from a database table?

Answer 20

by using the delete keyword

Question 21

How do you accidentally delete all rows from a table?

Answer 21

by not specifying what to delete

Question 22

What is a foreign key?

Answer 22

its a key that references another table

Question 23

How do you join two SQL tables?

Answer 23

use the join keyword then the key that both tables share

Question 24

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

Answer 24

youse the as keyword