Databases

What is a database?

A database is a collection of data. Its organized to structure information that is usually controlled by a database management system or refered to as DBMS. The most common type of database is typically modeled in rows and columns in. a series of tables to make processing and data query efficient. Most databases use Structured Query Language(SQL) for writing and querying data.

What is Structured Query Language(SQL)?

SQL is a programming language used by relational databases to query, manipulate, define data, and to provide access control. The data is stored in database objects that's called tables. A table is a collection of related data entries and it consists of columns and rows.

Let's have a table called Customers. The following example is to look at the "Customers" table:

SELECT * FROM Customers;

The keyword "SELECT" means to get access to the following table. "*" means for all the columns, "FROM" keyword is to refer to which table you want and Customers is the table. So all together the statement is saying we select to see all the columns from the table Customers.

Every table is broken up into smaller entities called fields. A field is a column in a table that is designed to contain information about every record in the table. There is also a row sometimes refer to as a record. A row is each indivdual entry that exist in a table. Think in the Customers table. A record is a horizontal entity in a table. A column is a vertical entity in a table that contains all information within a specific field in a table.