In this 3-part series, I want to walk you through the basics of databases and data structure.

These concepts are critical to new users of Power BI because of its ability to relate disparate sources of information.

• In Part 1, I’ll walk through a series of important database concept.
• In Part 2, we’ll talk about good data structure.
• Finally, in Part 3, we’ll talk about bad data structure and pitfalls to avoid.

At a high level, a database is a structured collection of data that is organized and stored in a way that allows for efficient storage, retrieval, and manipulation.

Databases are used to manage and store data in various applications, ranging from small personal projects to large enterprise systems.

Here's an overview of how a database works:

Data Structure

A database consists of one or more tables, each representing a specific type of data.

Each table is made up of rows (also called records or tuples) and columns (also called fields).

Rows represent individual instances of data, while columns define the attributes or properties of the data.

Data Types

Each column in a table has a defined data type that specifies the kind of data it can hold, such as numbers, text, dates, and more.

Data types help ensure data integrity and facilitate efficient storage and retrieval.

Schema Definition

The structure of the database, including the tables, columns, relationships, and constraints, is defined using a schema.

The schema acts as a blueprint for how the data is organized and how different tables are related to each other.

Data Manipulation

Databases allow for CRUD operations – Create, Read, Update, and Delete.

These operations are performed using specialized query languages like SQL (Structured Query Language).

SQL allows you to insert new data, retrieve specific data, update existing data, and delete data.

Indexing

Databases often use indexes to improve the speed of data retrieval.

An index is a data structure that stores a sorted or hashed copy of selected columns of a table, making it faster to search for specific values.

Normalization

To eliminate data redundancy and maintain data integrity, databases often use a process called normalization.

This involves breaking down data into smaller, related tables and establishing relationships between them.

Primary Keys and Foreign Keys

Each table typically has a primary key, which is a unique identifier for each row in that table.

Foreign keys are used to establish relationships between tables by referencing the primary key of another table.

This ensures data integrity and maintains the consistency of the relationships.

 Query Optimization

Databases optimize query execution to improve performance.

This involves techniques like query planning, indexing, caching, and using efficient algorithms to retrieve and manipulate data.

Concurrency Control

Databases handle multiple users accessing and modifying data simultaneously.

Concurrency control mechanisms ensure that changes made by one user do not interfere with changes made by other users, maintaining data consistency.

Transactions

A transaction is a sequence of one or more database operations that are executed as a single unit of work.

Transactions ensure that database operations are either fully completed or fully rolled back in case of errors, preserving data integrity.

Data Security

Databases implement access controls and security measures to ensure that only authorized users can access and modify specific data.

This includes user authentication, role-based access control, and data encryption.

Backup and Recovery

Databases regularly perform backups to ensure that data is not lost in case of hardware failures, software errors, or other unforeseen events.

These backups allow for data recovery to a specific point in time.

A database is a sophisticated system that efficiently organizes, stores, retrieves, and manages data.

It provides a structured environment for working with data, making it an essential component of modern software applications and data-driven decision-making.

Now, onto Part 2: Good Data Structure!