database

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.And knowing the SQL language is a very portable skill given that there are so many relational databases driven by almost the same language.

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

is the set of attributes

Question 7

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

Answer 7

SQL is a declarative programming language. In declarative languages, programmers describe the results they want and the programming environment comes up with its own plan for getting those results

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 where clause

Question 10

What are the benefits of formatting your SQL?

Answer 10

For readability

Question 11

How do you retrieve all columns from a database table?

Answer 11

The * asterisk is not in quotes

Question 12

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

Answer 12

with and order by clause
The order by clause comes after the from clause.
The order by clause is followed by a column name in “ double quotes.

Question 13

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

Answer 13

with limit clause
The limit clause comes last.
The limit clause includes a literal integer number with no quotes to specify the maximum number of rows that should be returned.

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

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

Answer 16

Data rows can be batch inserted into a database table by specifying more than one tuple of values, separated by commas.

Question 17

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

Answer 17

returning clause

Question 18

How do you update rows in a database table?

Answer 18

update keyword then the table

set the value on the column you want to update

Question 19

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

Answer 19

so it targets the specific rows

Question 20

How do you delete rows from a database table?

Answer 20

delete statement then “from” and target row

Question 21

How do you accidentally delete all rows from a table?

Answer 21

delete statement then the table or delete table then where = true