- Databases are a great tool to outsource the work of making a ruby file, CSV, or PStore
- Databases are seperate from apps themselves, so any language apps can use any databases (MySQL, PostgreSQL, SQLite, etc.)
- The interface to databases is text
- Dont usually come with a GUI (graphical user interface) Regional databses (which powers most apps) use a special language called SQL (stuctural query language)
Working directly with Postgres
- Great one to use cause it is already installed on codespaces in github.
- Commands to set up a table
-
psql
- If this command went well, we should see postgres=#
-
\list
- displays all current databases on this computer
-
CREATE DATABASE my-db
- the name of the database should be snake_case
-
\connet my-db
- to enter databases
-
\dt
- lists all the tables in the db, this means “describe tables”. the realtion comes from the term “relational databases” a ‘relation’ is a set of multiple records. not related to “relationships”, in the context of one to many, or many to many, or one to one
-
CREATE TABLE contacts (
id SERIAL PRIMARY KEY,
-
first_name TEXT,
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last_name TEXT,
date_of_birth DATE )
- standard creation of a contact for use
-
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SELECT first_name, last_name FROM contacts
- use
*
instead to see all
- use
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INSERT INTO contacts
(all the values above)VALUES ('mary', 'webby', '1999, 29, 12')
- place single quotes around each intserted value.
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