Coding Basics: Database

1K Blog Marathon: Day 60

When I was starting to learn programming, I didn’t know a Database. So when saving data, I am using a text file, I create it dynamically (if not existing), read the text inside, and update if needed. On the second semester, our instructor teach us MS Access – so that’s when my question is answered!

Definition of Terms

Database is a collection of data in digital format. Think of it as a warehouse, but instead of a building, it resides in a computer. It is composed of one or many tables, which is composed of fields or columns. This columns are defined by data types.

Table is a group of fields.

Field is a table column (vertical) that handles one type of data, ex. String, numbers, datetime, etc. You can also refer to it as column header.

Entity is a table row (horizontal) that handles the actual data. An entity is one item in a table. It is a collection of information about an item defined by the field, ex. A person entity is composed of (name) Ian, (age) 27, (gender) Male.

CRUD – Create, Read, Update and Delete.

DBMS – Database Management System, a software that the user is interacting with the database via front user interface.

Types of Database Model

Hierarchical – the table-field-entity relations are organized in a tree-like structure, with branches and nodes. This requires the child record should have only one parent. In contrast, the parent can have one of more child records.

Object-Oriented – database that represent data in the form of objects and classes, like in object-oriented programming. Each item is treated as object, with properties like Polymorphic, Inheritable, Encapsulate able, and Abstract.

Network – Unlike Hierarchical, Network Database Model allows a record or entity to have multiple parent and multiple child records. In real life, multiple records can be updated by multiple users, forming a web-like structure.

Relational – This structure allows a table to have a “relation” to other tables using a linking field called “keys”. Primary Key is a unique field that is similar in the two tables, Foreign Key is a key from other table linking to a table. For example, In Table Employee, EmpID is used as Primary Key to link or form relation to another table, Table Salary.

NoSQL– Literally “No SQL”, or uses limited SQL if possible. Unlike tabular database models, NoSQL is a more flexible model because it is “horizontal” in essence – there is no hierarchy, not very restrictive compared to regular databases.

“And that’s one blog, stay hungry!”

You can have data without information, but you cannot have information without data

Daniel Keys Moran