How a database table is organized

A relational database consists of tables. Tables consist of rows and columns, which can also be referred to as records and fields.
A table is typically modeled after a real-world entity, such as a product or customer.
A column represents some attribute of the entity, such as the list price of a product or a customer’s email address.
A row contains a set of values for one instance of the entity, such as one product or one customer.
The intersection of a row and a column is sometimes called a cell. A cell stores a single value.
Most tables have a primary key that uniquely identifies each row in the table.
The primary key is usually a single column, but it can also consist of two or more columns (compound key).
In addition to primary keys, most database management systems (DBMS) let you define one or more non-primary (secondary)keys. In MySQL, these keys are called unique keys. Like a primary key, a non-primary key uniquely identifies each row in the table.
A table can also be defined with one or more indexes. An index provides an efficient way to access data from a table based on the values in specific columns. An index is automatically created for a table’s primary and non-primary keys.

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