SQL, also known as Structured Query language, is the cornerstone of relational database management. It is capable of providing crucial facts about procedures in sectors such as financing, healthcare, and e-commerce. This blog provides a beginner’s guide to SQL Server while offering a dive into its concrete objectives and support.
Table of content
What is SQL?
A common question is “what is the full form of SQL”. SQL stands for Structured Query Language. The original name of the language was SEQUEL, created for the IBM System R research database in 1970, but due to copyright issues, they changed the name to SQL.
SQL is a structured query language developed designed for interaction of data with the relational databases. It helps developers do work in an efficient manner with data by performing a task such as querying, updating, deleting and managing the data. Data in relational database is stored in structured tables with defined relationships. To manage and store this data, we have relational database management systems like SQL Server, MySQL, MS Access, etc. that use SQL as a standard database language.
Purpose of SQL
SQL is the standard language used for interacting with relational databases. It provides a systematic and organised approach toward creating,managing and manipulating data through a structured format. Much more about its use comes next:
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Data Storage and Organization
SQL is used in the definition and management of data storage in relational databases. Data is therefore stored in a structured table format, or rows and columns, for easy management, retrieval, and manipulation.
Purpose: Large amounts of information are made accessible and logical.
Example:
Create table employee100(
e_id int,
e_name varchar(15),
e_salary int);
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Data Retrieval
SQL mainly uses for retrieving specific data based on user-defined conditions in the large datasets. This is used for reports and dashboards primarily to extract data for business intelligence.
Search Operations: Fast location of relevant information.
Example:
Select e_id,e_name from employee100 where e_salary>100000;
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Data Manipulation
SQL provides for inserting, updating, or deleting records in the tables. It allows easy maintenance of changing business requirements.
Purpose: Maintain the data up-to-date
Example:
Insert into employee100 values(1, ‘Tanya’ , 50000);
Update employee100 set salary = 60000 where e_id=1;
Delete from employee100 where e_id=1;
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Data Integrity
SQL enforces the data integrity constraints to manage the accuracy and
Purpose: Prevents from adding up invalid and duplicate data
Integrity rules include:
PRIMARY KEY: Ensure unique and not null values in the table.
FOREIGN KEY: Helps to built relationship between two tables.
NOT NULL: Ensures a particular column cannot have null(empty) values.
SQL Fundamentals
Key Components of SQL
Database: A database contains records, and to create, modify, or delete these records SQL queries are used. An SQL query can either be an action query like delete or create or a select query like select or use. These queries are used to find specific data, perform actions on it, or just display data by filtering based on specific criteria.
Table: A database structure that contains rows or records, column or fields. It maintains a specific data type in a structured manner.
These are SQL commands that provide interaction with the database such as retrieval of existing data or modification. Examples include SELECT, INSERT, UPDATE, and DELETE.
Query: A SQL statement or command is one that retrieves, inserts updates or deletes a database. For instance, SELECT, INSERT, UPDATE, and DELETE
Primary Key: It uniquely identifies each record in the table. It ensures there are no duplicate or NULL values in the column specified for the primary key.
Joins: Combining related information from two or more tables based on a common column. Used to retrieve information in one query.
CRUD Operations: Core database operations are Create, Read, Update, and Delete records.
SQL Architecture and Database Types
Types of Database Architecture
We have two types of database architecture:
File Server Architecture
In the file server architecture, files are located on the local system. It is useful for sharing information across a network. The client sends a request for a file over the network, and the file server forwards the file to the client. This is considered to be the most primitive type of data service used for exchanging information over a network. The file server provides access to remote server processors too.
Here is an example to understand the implementation of the file server.
Suppose, you have an Excel file, and one of your friends requests you to send that file for some information. So, you send a copy to your friend. Now when you make any changes in your original Excel file, those changes would not be reflected in the file which is with your friend.
In this example, you are a file server and your friend is the device requesting the information. We can conclude on the file server architecture by quoting that the server acts as a sorting device and only one person at a time can have access to it.
Client-Server Architecture
In the client-server architecture, the database is the server and any application that uses the data is a client.
Here is an example to explain the working of this server. Consider three OLE DB components or client systems accessing the database at the same time. The systems have logged into the IRCTC website to know the number of trains running from X destination to Y destination.
The client system sends the request to the network server. The network server sends the same request to the database and the final result is sent to the client system. This process is conducted when one system sends the request. But in real-time, there will be n number of systems and there can be multiple requests that are sent at a time for the same data. The database server will have to process all the requests simultaneously and send back the requested data to the client systems.
Types of Databases
The databases are classified into various databases depending upon the usage requirements:
- Centralized database
- Distributed database
- Personal database
- End-user database
- Commercial database
- NoSQL database
- Operational database
- Relational database
- Cloud database
- Object-oriented database
- Graph database
Key Features of SQL
Features of SQL
Now we are good to go with SQL! As discussed before SQL full form is a structured query language, it helps you to communicate with the database by commands. Here are some of the features of SQL Database:
- It allows users to extract data from the relational database.
- It allows users to create databases and tables.
- It allows updating, inserting, deleting, and altering databases and tables.
- It provides security and allows to set permission.
- Allows people to handle data in new ways.
The SQL Process: Step-by-Step-Guide
SQL Process
When you want to run SQL Queries on any DBMS system, you must first decide the best method for carrying out your request, and the SQL engine will determine how to interpret that task.
The following are some important components of the SQL process:
- Query Dispatcher: The dispatcher’s task is to send the query request to either CQE or SQE, depending on the query’s attributes. The dispatcher is in charge of handling all inquiries. It can’t be avoided.
- Optimization Engines: After considering several factors related to the objects referenced and the conditions defined in the query, including the Optimizer Goal, the Query optimizer determines the most efficient way to execute a SQL expression.
- Classic Query Engine: For any fields that are empty, CQE will use default values to map data into the record buffer. For fields that aren’t empty, SQE just maps data to the record buffer.
- SQL Query Engine: To access data in relational structures, a SQL query engine interprets SQL commands and language. Many people use SQL query engines to perform CRUD (create, read, update, and delete) operations and implement data policies that are required by relational data models and database management systems.
Benefits of SQL
SQL Advantages
Since SQL can work with any database, it is the most widely used language for database access. The databases in which you interact are programs that allow clients to logically store and manage information. With SQL, we can have the following advantages.
- SQL offers data access to users in relational databases.
- Users may use this feature to define the data.
- Identifying and modifying the data in a database is easy with SQL
- We can create, delete, alter the data in the database anytime.
- It Allows SQL modules, libraries, and pre-compilers to be embedded within other languages.
- Database views, stored procedures, and functions can be built with SQL.
What is SQL used for?
SQL is the standard language for interacting with and maintaining databases, and is often used for organizing, managing, and retrieving large data amounts in finance, health care, or e-commerce industries. In turn, the mastery of SQL enhances any professional’s competitive advantage through making it easier to perform more sophisticated data-related tasks, especially in informing business decisions, ensuring compliance, and in general data-driven strategies.
Why Learn SQL?
One of the major skills needed in today’s data-driven world is SQL: it’s a Structured Query Language used to access relational databases.
Why SQL matters:
- Data Science and Analytics Foundation
SQL is an entrance into advanced analytics that forms a basis for data processing and visualization learning tools such as Python and R. Its application is therefore key for one interested in pursuing data science or machine learning
- Universal Database Language
SQL is the standard for managing and querying relational databases such as MySQL, PostgreSQL, and SQL Server. It is widely used in industry, so skills are transferable across platforms.
- Effective Data Management
SQL simplifies dealing and analyzing large datasets since one can precisely query a set to retrieve or manipulate it. This makes SQL necessary for reporting, trends, and data-driven decision making.
Mastering SQL will open job roles from a data analyst to a database administrator, and more importantly, a Business Intelligence Developer. One of the most in-demand skills in industries ranging from tech to finance and even healthcare
- Streamlines Data Security and Integrity
SQL supports role-based access control, constraints, and encryption that ensures data integrity and is also confidential. Such features make it very important for any organization dealing with sensitive information.
SQL Skills in Demand
Most organizations are looking for professionals in SQL skills. Some in-demand SQL skills are:
- Database structures
- Creating a database with SQL
- SQL statements and clauses
- SQL database management
- MySQL and PostgreSQL
- Master PHP
With these in-demand SQL skills you can land in positions as follows:
- Database administrators(DBA)
- Database Migration engineer
- Data scientist
- Big data architect