Get Your Data Fix with These Database Concepts

Get Your Data Fix with These Database Concepts - You'll Be Hooked! was initially published on Wednesday January 11 2023 on the Tech Dev Blog. For the latest up-to-date content, fresh out of the oven, visit https://techdevblog.io and subscribe to our newsletter!

Introduction

A database is a collection of data that is stored in a structured format and can be accessed electronically. Databases are used to store and retrieve data efficiently, and are an integral part of many software systems. There are many different types of databases, including relational databases, NoSQL databases, and object-oriented databases. As a programmer, it is important to understand the key concepts related to databases and how to work with them effectively.

Tables and Columns

A database table is a collection of data that is organized into rows and columns. Each column represents a piece of data, and each row represents a unique record. For example, a table of employees might have columns for the employee's name, address, and salary, and each row would represent a different employee.

Primary Keys

A primary key is a column or set of columns that is used to uniquely identify each row in a table. A primary key is usually defined as a column that does not contain null values and is unique for each row.

Foreign Keys

A foreign key is a column or set of columns in a table that refers to the primary key of another table. Foreign keys are used to establish relationships between tables.

Indexes

An index is a data structure that is used to improve the performance of database queries. Indexes allow the database to quickly locate specific rows of data, rather than having to scan the entire table. Indexes can be created on one or more columns of a table, and can be either unique or non-unique.

CRUD operations

CRUD stands for Create, Read, Update, and Delete, and it refers to the four basic operations that can be performed on a database.

Create: This operation is used to add new records to a database.
Read: This operation is used to retrieve data from a database.
Update: This operation is used to modify existing records in a database.
Delete: This operation is used to remove records from a database.

By extension, a "CRUD app" is an app whose features are mostly limited to these four operations.

Types of Databases

There are several types of databases that are commonly used:

Relational databases: These are the most common type of database and store data in tables with rows and columns. Relationships between different tables can be established using keys. Examples of relational databases include MySQL, Oracle, and Microsoft SQL Server.
NoSQL databases: These databases are designed to handle large amounts of data that is not easily modeled in a relational database. NoSQL databases are often used for big data and real-time web applications. Examples of NoSQL databases include MongoDB, Cassandra, and Redis.
In-memory databases: These databases store data in memory rather than on disk, which makes them much faster than other types of databases. In-memory databases are often used for real-time processing and analysis of data. Examples of in-memory databases include MemSQL and VoltDB.
Graph databases: These databases A graph database stores data in the form of nodes and edges, which represent the relationships between the data. These databases are designed to handle complex relationships and connections between data points, and are used in applications that require fast querying and manipulation of complex relationships. Examples of Graph databases include Neo4j, OrientDB and ArangoDB.

Database Management Systems (DBMS)

A database management system (DBMS) is a software application that is used to create, maintain, and interact with databases. DBMSs provide a way to store, retrieve, and manipulate data in a database. Some examples of DBMSs include MySQL, Oracle, and Microsoft SQL Server.

Structured Query Language (SQL)

Structured Query Language (SQL) is a programming language used to interact with relational databases. SQL is used to create, modify, and query database structures and the data stored in them. Here are some basic SQL commands:

SELECT: used to retrieve data from a database
INSERT INTO: used to insert new data into a database
UPDATE: used to modify existing data in a database
DELETE: used to delete data from a database

Here is an example of a simple SQL query to select all rows from a table called "users":

SELECT * FROM users;

ACID Properties

ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that ensure that transactions in a database are processed reliably. These properties are important for maintaining the integrity of a database and ensuring that data is accurately reflected in the database.

Transactions

A transaction is a unit of work that is performed against a database. Transactions are used to ensure that database operations are atomic, consistent, isolated, and durable (ACID). This means that either all of the operations in a transaction are completed, or none of them are, and that the database is left in a consistent state regardless of whether the transaction is successful or not. Transactions are important because they help to ensure the integrity and reliability of a database.

Normalization

Normalization is the process of organizing a database in a way that reduces redundancy and dependency. Normalization is important because it helps to minimize the amount of data duplication, which can lead to problems such as data inconsistencies and data integrity issues. There are several normal forms that can be used to normalize a database, with the most common being the first, second, and third normal forms.

Stored Procedures

A stored procedure is a pre-compiled collection of SQL statements that can be executed as a single unit. Stored procedures are often used to encapsulate complex logic or to improve performance by reducing the amount of SQL that needs to be sent to the database.

Triggers

A trigger is a piece of code that is automatically executed by the database in response to certain events. Triggers can be used to enforce business rules or to perform additional actions when data is inserted, updated, or deleted from a table.

Conclusion

In this guide, we have covered the main concepts related to databases as a programmer. Understanding these concepts will help you to work effectively with databases and build software systems that are reliable, efficient, and scalable.