Databases

Database management systems (DBMS) contains tables with records, which are rows that have a value for each column.
- Every table has columns and rows
- A column has a name and a type
- A row has a value for each column
The Structured Query Language (SQL) is perhaps the most widely used programming language used to manage databases.
- It is a domain-specific language.
- It is also a declarative programming language.

Declarative Programming

In Declarative programming:
- A program is a description of the desired result
- The interpreter will fiture out how to generate the result.
This contrasts to Imperative Programming where we have to specify the full instructions about how to get there.
Because of this, Imerpative programming is a lot more versatile, whereas the declarative language is more domain specific.

A select statement creates a new table and displays it.
- We “create” a new version of the table and that table is what we display.
A create table statement names the result of a select statement. This actually creates a new table and assigns a name to it.

A select statement can specify an input table using a from clause
A subset of the rows of the input table can be selected using a where clause
An ordering over the remaining rows can be declared using an order by clause
Syntax: SELECT <column names> FROM <table name> WHERE <condition> ORDER BY <order>;
- Column names are seperated by commas
Syntax: SELECT <expression> AS <name>, <expression> aAS <name>,...
We may also create a table with select statements
- CREATE TABLE <track_names> AS SELECT <column names> FROM <table name> WHERE <condition> ORDER BY <order>;