PostgreSQL Flashcards
What is PostgreSQL and what are some alternative relational databases?
MySQL, SQL server, and Oracle.
What are some advantages of learning a relational database?
categorizing data, accuracy, ease of use, collaboration, security.
What is one way to see if PostgreSQL is running?
sudo service postgresql status
What is a database schema?
a collection of tables.
What is a table?
objects that contain all data in a database.
What is a row?
a single group of related content within a table.
What is SQL and how is it different from languages like JavaScript?
SQL is where you learn how to work with a database. JavaScript is a full on programming language that is later leveraged to help you write server-sided code.
How do you retrieve specific columns from a database table?
select “column name”
How do you filter rows based on some specific criteria?
where “column name” = ‘specific name
What are the benefits of formatting your SQL?
readability and consistent style.
What are four comparison operators that can be used in a where clause?
=, <, >, or
How do you limit the number of rows returned in a result set?
limit number;
How do you retrieve all column from a database table?
select *
How do you control the sort order of a result set?
desc = descending or asc = ascending
How do you add a row to a SQL table?
insert statement
What is a tuple?
internal representation of a row in a table in PostGreSQL
How do you add multiple rows to a Sql table at once?
select property=’string’ property=’string’
How do you get back the row being inserted into a table without a separate select statement?
returning *;
How do you update rows in a database table?
insert into
Why is it important to include a where clause in your update statements?
So you don’t update everything.
How do you delete rows from a database table?
delete command
How do you accidentally delete all rows from a table?
if you don’t include a where clause.
What is a foreign key?
a column in a table that points to a primary key or unique key column in the same or another table.
How do you join two SQL tables?
using the join keyword.
How do you temporarily rename columns or tables in a SQL statement?
as
What are some examples of aggregate functions?
sum(), avg(), count()
What is the purpose of a group by clause?
group two tables together.
