1
Q
What is PostgreSQL?
A
its an open source relational database.
2
Q
What is one way to see if PostgreSQL is running?
A
sudo service postgresql status
3
Q
what is a database schema?
A
Collection of tables and how they are structured
4
Q
What is a table?
A
- List of rows with the same attributes or columns
5
Q
- What is a row?
A
- List of values that add up with the attributes in the table
6
Q
- What is SQL and how is it different from languages like JavaScript?
A
- Structured Query Language is the primary way of interacting with relational databases. It’s a declarative language
7
Q
How do you retrieve specific columns from a database table?
A
- Select “column” from “table”
8
Q
- How do you filter rows based on some specific criteria?
A
- Where clause with pretiquite (where “firstName” = ‘Rob’)
9
Q
- What are the benefits of formatting your SQL?
A
- Makes it easier to read
10
Q
- What are four comparison operators that can be used in awhereclause?
A
- =, < , >, !=
11
Q
- How do you limit the number of rows returned in a result set?
A
- Limit
12
Q
- How do you retrieve all columns from a database table?
A
- Select *
13
Q
- How do you control the sort order of a result set?
A
- Order by column name (desc)
14
Q
- How do you add a row to a SQL table?* What is a tuple?
A
- Insert into “table” (“column”, “column”, “column”)
values (‘name’, ‘name’, name’)
15
Q
What is a tuple?
A
- A list of values in parenthesis
16
Q
- How do you add multiple rows to a SQL table at once?
A
- Add more than one tuple of values separated by commas.
values (‘Ostrich Pillow’, ‘Feel comfy and cozy!’, 99, ‘self care’),
(‘Tater Mitts’, ‘Scrub some taters!’, 6, ‘cooking’)
17
Q
- How do you get back the row being inserted into a table without a separateselectstatement?
A
- Returning *;
18
Q
- How do you update rows in a database table?
A
- Update “table” set “column” = ‘value’ where (pretiquite)
19
Q
- Why is it important to include awhereclause in yourupdatestatements?
A
- it will update every row
20
Q
*
* How do you delete rows from a database table?
A
- Delete statement
21
Q
- How do you accidentally delete all rows from a table?
A
- Not including a where clause
22
Q
When do you not put single quotes around values?
A
numbers and booleans do not need quotes
23
Q
What is a foreign key?
A
Column you can use to link to another table
24
Q
How do you join two SQL tables?
A
join “films” using (“filmId”)
25
How do you temporarily rename columns or tables in a SQL statement?
-- as - - keyword
26
What are some examples of aggregate functions?
avg("column") or count(*)
27
What is the purpose of a group by clause
your aggregate is applied to those groups.
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