SQL Server DBA Tutorial

What is an SQL Server?

SQL Server is a relational database management system that Microsoft has developed. It is mainly designed and built to compete with the Oracle and MySQL databases. SQL Server is primarily used for storing and retrieving data. Its key interface tool is SQL Server Management Studio, which runs on both 64-bit and 32-bit environments.

To understand SQL Server completely, we first need to learn the SQL language. SQL is the query-processing language used to process data into relational databases. In the client-server model, the database server is a program that offers multiple services. Accordingly, we have referred to an SQL server as a database server that uses SQL as a query language.

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Why SQL Server?

Unlike most other desktop apps, the SQL Server can function like a client-server database system. These systems operate either on a central server or on many central servers. It enables several users to access the data instantly from the network. Users can access the database through an application. Using the database, you can save the data and make it available. In SQL Server, some helpful features allow CRM applications to deliver their functionality. Working professionals can be in various nations, access the data through the browser, and update it.

Versions of SQL Server

There were approximately 19 distinct models of SQL Server, and inevitably, some were recognizable. They are listed below:

• The primary one emerged in 1989 as part of a project to port the Sybase SQL Server to OS/2.
• With Server 4.2 for NT, released in 1993, the SQL Server entered Windows NT.
• In 1995, SQL Server 6.0 was launched, and the Sybase cooperation ended.
• In 1998, SQL Server 7.0, during which source code was transformed from C to C++, was launched.
• SQL Server 2005, where the old Sybase code was withdrawn, which was unveiled in 2005.
• New features, such as Availability Groups and Always On SQL Server Failover Cluster Instances, have been included in SQL Server 2012, providing options to enhance the availability of databases.
• New in-memory functionality for tables was introduced by SQL Server 2014, which made them fit entirely into memory.
• SQL Server 2017, or version 14.0, codenamed vNext, was launched in 2017 and added support for Linux.
• SQL Server 2019, or version 15.0, codenamed Seattle, was launched in 2019. It provides Always On availability groups, ensuring effective resource management and improved database availability.
• SQL Server 2022.

SQL Server Usage:

The key usage for MS SQL Server is as follows:

• Its main objective is the creation and maintenance of databases.
• It is used for data analysis with SQL Server Analysis Services (SSAS).
• It helps to produce reports with SQL Server Reporting Services (SSRS).
• It helps to perform ETL operations with SQL Server Integration Services (SSIS).

SQL Server Architecture

SQL Server architecture is based on client-server and aims at end-users, called clients, who send queries to the MS SQL server installed on a specific computer. Once the processing input data is requested, the server will deliver the expected result. This server is vacant as a separate program. It is in charge of managing any statements, instructions, or commands in the database. The SQL server database engine will control data processing, storage, and security. So, it is the main component of the SQL server.

This architecture is built on the client-server model, where users share and access the data on the server through client apps. Knowing internal design or architecture is the best method of learning technology.

SQL Server looks very simple, but many processes run internally in the background to respond to the requests. MS SQL Server architecture is divided into different categories, such as;

• General Architecture
• Data file Architecture
• Memory Architecture
• Log file Architecture

Let us discuss them in brief.

1) General Architecture: 

The general architecture deals with network packets, queries, protocols, servers, etc. 

2) Data File Architecture:

This architecture consists of various components such as file groups, extents, files, pages, etc. In this, the database is divided into database files that help in administration and distribution.

3) Memory Architecture

It aims to reduce disk read writes, which is the most essential part of SQL server architecture.

4) Log file Architecture

The SQL server transaction log helps to execute logical operations where the transaction log works as a string of log records. 

According to the architecture, the SQL Server has three main components: Network Protocols, SQL OS, and database engine.

SQL OS: It is used for the first time in SQL 2005. In the past, it was only intended for small and medium-sized applications. Microsoft is upgrading SQL Server into SQL 2005 to accommodate high-end enterprise databases. It is a layer located between the Windows OS and the database engine.

SQLOS manages many OS services, including I/O and memory management, threading, scheduling, synchronization, and exception handling.

                                                                              [Related article: Exception Handling in SQL Server]

Database Engine:

It is what SQL Server architecture is all about. It is the second layer in the architecture, providing connectivity among user connections using the network protocol and the SQL Server OS to execute. It explains the logical architectures of the database objects like views, tables, triggers, and stored procedures that work with the relation engine and physical architecture to meet customer requests. The database engine is made up of two components:

Storage Engine:

It displays physical database architecture, data storage, and retrieval from the buffer manager and storage system.

Relational Engine:

This engine is responsible for assessing and executing user requests. It decides what is the most effective way to execute a query. It is also known as the Query Processor. The main tasks performed by relational engines are memory management, Query processing, distributed query processing, buffer management, and thread and task management. 

Network Protocol:

It is entirely responsible for the client connectivity of the SQL Server database engine. In addition, it has another protocol called VIA. Microsoft has made the VIA hardware protocol obsolete. This protocol will not be seen in the most recent SQL Server Configuration Manager.

There are three main protocols for network connectivity:

1) Shared Memory: This protocol is simple and needs no configuration. It runs on the same system in which SQL Server is installed. Communication between the client and the server does not exist.

2) TCP/IP: This is the widely used client-server communication protocol. To enable it, we can use the SQL Server Configuration Manager.

3) Named pipes: This is mainly used for LAN connectivity and may be enabled from the SQL Server configuration manager.

SQL Server Services & Tools:

MS SQL Server includes Business Intelligence (BI) and Data Management tools and services. SQL Server consists of the following tools and services for managing data:

• SQL Server Integration Services transfers different types of data from one source to another by importing, exporting, transforming, and loading. It translates raw data into useful information in the future.
• SQL Server Data Quality Services: This develops a knowledge-based data quality product that is used to correct, enrich, standardize, and duplicate data. We may also use it to cleanse data through cloud-based reference data services.
• SQL Server Master Data Services: It manages an organization's data master set. It organizes data into models and creates data update rules and controls that update these data.
• SQL Server Data Tool: This tool helps design and develop databases.
• SQL Server Management Studio: Using this tool, we can deploy, monitor, and manage SQL Server databases.

                                                                                                 [ Related Article: SQL Server Data Tools ]

 SQL Server is comprised of the following data analysis tools and services:                                                                                

1) SQL Server Analysis Services:

This tool is designed for faster and deeper data analysis and mining and includes ML capabilities as well. Python and R languages are embedded with SQL Server for advanced analytics.

2) SQL Server Reporting Services:

It has a decision-making feature and a collection of tools and services to create, deploy, and handle reports. Hadoop is part of that tool.

SQL Server has the following key components as well:

• SQL Server: It allows us to pause, resume, start, and stop the MS SQL Server instance.
• SQL Server Agent: This computer program functions like a task scheduler and can be used when needed.
• SQL Server Browser: It gets the request from the user and connects to the corresponding SQL Server instance.
• SQL Server Full-Text Search: This element allows you to search for all document keywords that may or may not correspond exactly to the search criteria. It will enable the user to execute full-text requests with character data in the tables.
• SQL Server VSS Writer: This is used when SQL Server does not function to back up and restore data files.

SQL Server Instances

SQL Server installation is an instance. Multiple instances can be installed on a specific machine, but the default will be only one. It is the accurate copy of databases, server files, and security credentials.

SQL Server is subdivided into two types: 

• Primary Instances: The primary instance is accessible in two ways: using the server name or the IP address. It is always unique.
• Named Instances: This can be accessed by adding a backslash and an instance name.

Top 20+ frequently asked SQL Server Interview Questions & Answers for freshers & experienced professionals.

Benefits of SQL Server Instances:

The SQL Server instance has the following benefits:

• Installing various versions on a single machine: It enables us to install several versions on one computer, each working separately from the other.
• Cost Reduction: It reduces the cost of operating SQL Server. We can get various services from various instances, so we need not purchase a license for anything.
• Maintaining development, production, and test environments individually: The main benefit of running more than one version of SQL Server on one computer is that you may differentiate your output, development, or test environments separately.
• Minimize temporary database issues: If all services are executed on one instance of SQL Server, there is an elevated risk of issues. If such problems occur in different cases, they may be avoided.
• Separate security privileges: When different instances of SQL Server execute different services, it will be easy to focus on the security of the instance that executes the sensitive service.
• Maintain a standby server: A failure of the SQL Server instance may cause a service interruption. It explains how important it is to have a backup service available to pick up if the primary server fails. This functionality simplifies the execution of SQL Server instances.
  
  

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Let us move further in this tutorial and learn more about SQL Server.

Components of SQL Server

The latest SQL Server versions are launched every 18 months. Significant developments often do not only make marketing headlines but also deliver improvements in productivity and performance. In the consolidated updates, Microsoft began to incorporate product releases.

1) Database Engine:

This section of SQL Server builds and drives relational databases. The diagram below illustrates an overview of database engine architecture.

2) SQL Server Analysis Services:

This section manages SQL Server data analysis. They build Online Analytical Processing cubes, which are highly developed programming objects that can organize data within the relational database. The diagram below provides an overview of the SQL Server 2005 analysis services architecture.

3) SQL Server Reporting Services:

It is an SQL Server component that offers reporting despite the database operating system. The diagram below illustrates an overview of SQL Server reporting services architecture.

4) SQL Server Integration Services:

The SQL Server will perform the Extract, Transform, and Load or ETL process of the SQL Server. The diagram below illustrates the overview of SQL Server Integration Services architecture.

SQL Key types:

Keys function in the database tables as a blend of single or multiple fields. They are used as per the specifications to retrieve the records or data from the rows in a table. It is also feasible to use these keys to determine the relationship between tables. Keys categories include the following:

• Super Key: A set of one or more keys that would uniquely mark a record in the table.
• Candidate Key: A set of one or more fields that would be able to define a record uniquely. A table can contain several candidate keys, each of which can be a primary key.
• Primary Key: A set of one or more fields uniquely defining a record that cannot recognize null or duplicate values in the database table.
• Alternate Key: A candidate key that does not serve as a primary key.
• Foreign Key: A field in a database table that, in another table, acts as a primary key and is used to establish a relationship between tables. The null and duplicate values will be considered.
  
  

In the RDBMS system, SQL allows users to access data. It assists you in describing the data and will enable you to define the data in a database and manipulate that relevant data. You can build and drop databases and tables with SQL commands in the DBMS. SQL provides you with the ability to use the function in the database, create a view, and stored procedure. On tables, procedures, and views, you may indeed set permissions. There are five types of SQL queries used extensively.

• Data Definition Language (DDL).
• Data Manipulation Language (DML).
• Data Control Language(DCL).
• Transaction Control Language(TCL).
• Data Query Language (DQL).

What is DDL?

The Data Definition Language helps you describe the structure or schema of the database. The following are the types of DDL commands which will be used in SQL:

1) CREATE

CREATE statements are used to determine the schema of the database structure:

Syntax:

CREATE TABLE TABLE_NAME (COLUMN_NAME DATATYPES[,....]);

Examples:

Create a database university;

Create table students;

Create view for_students;

2) DROP

Delete tables and databases from RDBMS by dropping commands.

Syntax:

DROP TABLE;

Examples:

Drop object_type object_name;

Drop database academy;

Drop table scholar;

3) ALTER

The Alters command enables you to manipulate the database structure.

Syntax:

• To add a new column to the table:

ALTER TABLE table_name ADD column_name COLUMN-definition; 

• To modify an existing column in the table:

ALTER TABLE MODIFY(COLUMN DEFINITION....);  

Example:

Alter table hkr99, add subject varchar;

4) TRUNCATE:

This command was used to erase all the table rows and free the space containing the table.

Syntax:

TRUNCATE TABLE table_name;  

Example:

TRUNCATE table scholars;

What is DML

The Data Manipulation Language (DML) lets you alter an instance of a database by inserting, modifying, and deleting its data. In a database, it is responsible for implementing all types of data modification. Three fundamental constructs allow users and database programs to fill in data and information:

In SQL, here are a few important DML commands:

• INSERT
• UPDATE
• DELETE

1) INSERT

It is an SQL query statement that is used to insert data into the row of a table.

Syntax:

INSERT INTO TABLE_NAME  (col1, col2, col3,.... col N)  

VALUES (value1, value2, value3, .... valueN);  

Or 

INSERT INTO TABLE_NAME    

VALUES (value1, value2, value3, .... valueN);  

Example:

INSERT INTO students (RollNo, FIrstName, LastName) VALUES ('60', 'Tom', Erichsen');

2) UPDATE

This command is used to update or alter the value of a table column.

Syntax:

UPDATE table_name SET [column_name1= value1,...column_nameN = valueN] [WHERE CONDITION]

Example:

UPDATE students    SET FirstName = 'Peter', LastName= 'Thompson' WHERE StudID = 10;

3) DELETE

To delete one or more rows from a table, this command is used.

Syntax:

DELETE FROM table_name [WHERE condition];

Example:

DELETE FROM students WHERE FirstName = 'Peter';

What is DCL?

DCL (Data Control Language) contains commands that are useful for giving "rights & permissions." such as GRANT and REVOKE. Other permissions govern the database system parameters.

Examples of DCL commands:

The following are the DCL Commands:

• Grant
• Revoke
  
  

1) Grant

This command is used to provide a database with user access privileges.

Syntax:

GRANT SELECT, UPDATE ON MY_TABLE TO SOME_USER, ANOTHER_USER;

Example:

GRANT SELECT ON Users TO'Tom'@'localhost;

2) Revoke

It is useful for backing permissions from the user.

Syntax:

REVOKE privilege_nameON object_name FROM {user_name |PUBLIC |role_name}

Example:

REVOKE SELECT, UPDATE ON student FROM BCA, MCA;

What is TCL?

Inside the database, the transaction control language or TCL commands deal with the transaction.

1) Commit

This command is used to save all the transactions in the database.

• Syntax:

Commit;

• Example:

DELETE FROM Students WHERE RollNo =25;  

COMMIT;

2) Rollback

You can undo transactions that have not already been saved to the database using the rollback command.

• Syntax:

ROLLBACK;

• Example:

DELETE FROM Students WHERE RollNo =25;

3) SAVEPOINT

You can set a savepoint inside a transaction with this command.

• Syntax:

SAVEPOINT SAVEPOINT_NAME;

• Example:

SAVEPOINT RollNo;

What is DQL?

The Data Query Language (DQL) is used to extract data from the database. Only one command will be used by DQL:

SELECT:

This command assists you in selecting an attribute based on the condition that the WHERE clause describes.

Syntax:

SELECT expressions FROM TABLES WHERE conditions; 

Example:

SELECT FirstName FROM Student WHERE RollNo > 15;

SQL Server instance

The SQL Server instance refers to the Database Engine instance. It is a copy of sqlservr.exe that can be executed on the operating system. Several system databases would be able to manage each of these instances. It means that multiple Database Engine instances can be run independently of the other instances on a computer.

You can install these instances at any time, even after the SQL Server has been running for some time on the system. The instances allude primarily to the database engine and the supporting components. For client tools, they do not apply. The diagram below illustrates the overview of SQL Server 2014 instance architecture.

Benefits of Instances:

The sky is the limit when it comes to different examples. The reasons can differ throughout various companies. These are some of the benefits provided by SQL Server Instances.

• Functional or Load testing: Load testing corresponds to the loading of various codebases and the synchronization of load testing with the instances. The load testing must then be performed to restart all cases after they have been completed. Functional Testing allows numerous codebases to be independently evaluated with preallocated resources.
• Server Sharing: With SQL Server, a departmental solution can be considered. Several Server 1 instances can be used to share the server's resources equally. It is suitable for departmental payments.
• Server Consolidation: Multiple instances are integrated into one server here. Full SQL Server backups and restoration can be done for a single instance and retain the same features as the original server.
• Security: For third-party apps, multiple instances are very good. These require high SQL Server privileges in cases where you do not want to commit applications to the same instance.
  
  

Database Systems of Client/Server

Applications for the client-server are apps that allow the user to access data stored on the server. It does not matter to the computer system. Both of these may be workstations and may run on the same type of operating system. The servers would hold databases, and the workstations would allow users to access the databases. By using some other database program, a client/server database application can be built.

• Server: The server is a component of the database-storing client/server framework. The server program, which is also part of the DBMS that interprets the clients' commands, is also present. In the database, these commands are interpreted as operations.
• Client: The client's most significant task is to build a user interface. To the end-users, the computer itself is the client machine, and the program is the user interface. Users will normally not be able to comprehend that the process requires a server.

Tasks of Database Management 

In this process, multiple database management activities are involved. They are as follows:

1) Alteration of Configuration Settings for SQL Server: 

Most of the configuration settings can presently be changed through SQL Server Management Studio. The SP_CONFIGURE TSQL command also helps to modify the relevant settings.

2) Managing Information Reports for the Database Engine: 

Using SQL Server instances, proper management can be executed. In the framework, many generic ones are already incorporated.

3) Databases Detachment and Attachment: 

Database detachment means that the SQL Server instance is completely removed. However, the files would be kept intact and persist in the file system. When the database is connected again, the state of the database will stay intact.

4) Database Objects Scripting:  

Two levels of scripting features help the SQL Server task or action to be moved to a TSQL script. This scripting feature is a great way to automate the duties or settings of redundant administration. Even with being an expert, robust scripts can be produced easily.

5) The Database Restoration:  

The most crucial task is the building of backups and the recovery strategy. When making backups, it is vital to comprehend better the recovery models associated with the database.

SQL Server Editions and Features

In many editions, SQL Server is available. Below are different editions with their characteristics:

• Enterprise: It is the best edition and contains all the numerous SQL Server features available. It is intended for large companies and business admins.
• Standard: The characteristics available in this edition are lower than those of Business. When there is no need for advanced functionality, it finds use. These can be used by industries that do not require advanced features.
• Workgroup: In the remote offices of large corporations, this edition discovers opportunities.
• Web: This edition is used for web applications in particular.
• Express: This is an entry-level edition. In addition to 1 GB of memory, only 1 CPU can be used, and the maximum database capacity is 10 GB.
• Developer: It is licensed to only a single user for Testing, demo, and development and is identical to the Enterprise edition. Without any need for reinstallation, the Developer edition can be upgraded to the Enterprise edition.
• Datacenter: The recent major update for the new SQL Server 2008 R2 is the Datacenter Edition. In terms of memory, it has no limitations. It will assist even for more than 25 instances.
• Compact: This edition is free and available for the creation of mobile applications. 4 GB is the database's maximum allocated capacity.
• Enterprise Evaluation: A completely functioning and free SQL Server instance is provided in the Evaluation Edition. It is perfect for studying and implementing ideas and will immediately expire after six months.
• Business Intelligence: All of the features are incorporated in the Standard edition. PowerPivot and Power View are some advanced features that are also included. Many advanced online operations, indeed, are available.

Determining the version of SQL

If you'd like to know the version of your SQL, you have to implement the corresponding steps.

• Press Windows Key + S to start. You're going to get the Search Box.
• In the box, you should type "SQL Server Configuration Manager" and click Enter.
• Then, in the top-left frame, highlight SQL Server Services.
• You need to right-click on SQL Server (PROFXENGAGEMENT) and then click on Properties.
• The Advanced tab should be clicked.
• In the "Stock Keeping Unit Name" and "Version" columns, you can find the corresponding information. The column "Stock Keeping Unit Name" indicates the edition of SQL, and you can also see the "Version" of the editions.

Using SQL Server:

The following needs must be installed first in order to use SQL Server. Two types of installations exist:

• Stand-alone.
• Cluster-based.

Step 1: You need to download the Evaluation Edition from Microsoft's official website. You will find some files depending on the bit-version selected:

ENUx86SQLFULL_x64_ENU_Core.box

ENUx86SQLFULL_x64_ENU_Install.exe

ENUx86SQLFULL_x64_ENU_Lang.box

(OR)

ENUx86SQLFULL_x86_ENU_Core.box

ENUx86SQLFULL_x86_ENU_Install.exe

ENUx86SQLFULL_x86_ENU_Lang.box

Step 2: You can choose "Install.exe" to retrieve the appropriate files from the directories you have downloaded.

Step 3: Then you can double-click on the program "SETUP".

Step 4: On the left side of the SQL Server Installation Center screen, press Installation.

Step 5: The first preference you can find on the right-hand tab should be pressed.

Step 6: On the following screen that is displayed, you should press "OK".

Step 7: Select the "Next" button.

Step 8: You need to select the product key and click on Next to verify it.

Step 9: You have to select the checkbox to approve the license option and then click on Next.

Step 10: You must select the option to install the SQL Server feature and choose Next.

Step 11: You can select the Checkbox for Database Engine Services and then click Next.

Step 12: You should enter a named instance, provide an appropriate name, and then click the 

Next button.

Step 13: On the screen that is displayed, click on Next.

Step 14: You can select the names of the service accounts and the start-up types for the services listed and then proceed to the Collation tab.

Step 15: Make sure that the right collation type is selected, and then press Next.

Step 16: You must ensure that the selection of the authentication mode and the administrators are checked, and then press Data Folders.

Step 17: You have to select the directory locations specified above and then click Next.

Step 19: Press the 'Next' button.

Step 20: Select the installs above and then press the Install button.

You can start using SQL Server this way.

How do I create a new SQL Server?

The following steps must be implemented to build a new database on the SQL server:

Step 1: Open the Microsoft SQL Management Studio.

Step 2: You can connect to the database engine and use the credentials of the database admin.

Step 3: This server node should be extended.

Step 4: You should right-click on the Databases and then select the new Database option.

Step 5: You need to enter a name and then press the OK button.

Hence, SQL Server is the most highly useful database and is used across different apps. It helps you simultaneously manage multiple users, and it ensures that transactions monitor the properties of the chosen isolation level. So, learning SQL Server skills can bring profitable career opportunities in top MNCs. 

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Let us move further and learn about PostgreSQL in brief. 

What is PostgreSQL?

PostgreSQL is one of the most robust and open-source data management tools. This tool is based on the object-oriented database management system. This tool helps the user to extend all kinds of SQL language, offering many advanced features that store the data safely and support the scalability of the most complicated data. We can pronounce this PostgreSQL as (Post-gres-ql). It has more than 30 years of active database development and is used on many-core platforms. This tool supports almost all kinds of RDBMS features that are not present in other query language tools such as SQL and MySQL.

Take your career to the next level in PostgreSQL with HKR. Join PostgreSQL Online Training now.

History of PostgreSQL:

PostgreSQL was created by a computer science professor at the University of California named Michael Stonebraker. The original name of this tool was Postgres.

1986-> It was a Postgre project at the University of California, Berkeley

Michael Stonebraker project

The successor to the development of INGRES

1994-> First commercialized as an Illustra

1995-> Open-source development started

• After that, they ported to the SQL tool
• Then, the PostgreSQL global development group was formed

1997-> Ported to different languages like Japanese, they developed to support in Japan

1999-> First-time full-time developer and corporate support

2004-> Native window support

2006-> Supported by Sun.

Versions of PostgreSQL:

Let us know the different versions of PostgreSQL:

1996-> PostgreSQL 6.0

1997-> PostgreSQL 6.1 and PostgreSQL 6.2

1998-> PostgreSQL 6.3 and PostgreSQL 6.4

1999-> PostgreSQL 6.5

2000-> PostgreSQL 7.0

2001 -> PostgreSQL 7.1

2002-> PostgreSQL 7.2 and PostgreSQL 7.3

2003-> PostgreSQL 7.4

2005 and 2006-> PostgreSQL 8.0

Currently, we are using PostgreSQL 9.4.15

Features of PostgreSQL:

The major features of PostgreSQL are:

1) Portable:

• Written in ANSI C language
• It supports major operating systems like Windows OS and Linux OS, Mac OS, and UNIX OS platforms.

2) Reliability:

• Fully Acid Compliant
• Supports data transactions
• Supports the data types and provides Savepoints
• It provides Write-Ahead Logging (WAL).

3) Scalable:

• Uses Multi-versions
• Concurrency Control
• Supports Table Partitioning
• Supports Tablespaces
• Supports Parallel Sequential Scans

These are the major features of PostgreSQL.

Why is PostgreSQL?

It is an important question that comes to mind when you begin your journey as a PostgreSQL. Let me give you a brief idea of why it is PostgreSQL.

• PostgreSQL is an open-source and object-oriented relational database management support tool.
• PostgreSQL is a community-driven platform as it consists of the core team, committers, contributors and developers
• It's a free tool, and no company owns it.
• It offers great mailing list support.
• Available yearly new release upgraded versions
• Great performance-oriented and replications in the last few years
• License is more flexible and non-expensive than GPL
• The non-technical team can also work on this platform.
• These are all the most available features of PostgreSQL.

What are the advantages and disadvantages of PostgreSQL?

We have discussed the definition of PostgreSQL, its history, and its main features. Now I am going to discuss its advantages and disadvantages. Firstly, know the benefits of PostgreSQL.

Advantages of PostgreSQL:

• PostgreSQL is an open-source standard-compliant RDBMS tool for SQL. It supports all relational data types, views, and features of RDBMS.
• We can work on complicated data types.
• This tool supports users in creating their own data types or customized data creations.
• Strong community support to ask any queries related to the tool.
• Strong third-party support.
• Extensible and object-oriented tool.

Disadvantages of PostgreSQL:

• Performance could be better while working on a complex platform.
• Less popular compared to MySQL
• Hosting is poor.

These are the advantages and disadvantages of the PostgreSQL tool.

PostgreSQL Data Types:

PostgreSQL supports rich data types. Users can create their own data types. This PostgreSQL offers customized data type creations. With the help of the CREATE TYPE command, we can create new data types. 

The following data types are available in the PostgreSQL tool:

• Text data types
• Numeric data types
• Dates/Times data types
• XML data type
• JSON data type
• Boolean data type
• Bits data type
• Binary data type
• Network data type
• Arrays data type
• Boolean expression data type
• Temporal data types
• UUID data types
• Array data types
• JSON data types
• Data types for storing a network and geometric data.
• Data tables
• Data filters
• Data queries
  
  

Let us discuss one by one,

Character Data types:

Character Data types in PostgreSQL support storing text values. These character data types help to create the same internal structures. There are three types of character data types available:

• CHAR (n) -> In this, we can add fixed-length and blank characters
• VARCHAR (n) -> In this type, we can create a variable-length with a limit
• Text-> In this type, we can create data types with unlimited data lengths.

Numeric data types:

PostgreSQL supports two types of numeric data types.

• Integers -> to store integer data types
• Floating-point -> to store floating-point types.

Binary data types:

PostgreSQL supports storing binary data types; they can be octets or bytes. There are two types of binary data types available such as,

• Binary data types help you to store odds of zero values
• Storing non-printable octets.

On the other hand, a character string does not allow the storage of zero octets and disallows any other sequence of octet values.

Network data types:

Many network applications in PostgreSQL allow users to store network information such as IP addresses and sensors.

There are three types of network data types available those are,

• Cider
• Inet
• Macaddr

There are lots of advantages to using Network data types:

• Saving storage space
• Error checking, especially input errors
• Searching data by subnet

Text search data types:

This PostgreSQL supports two types of data, which are mainly designed to create or help search for the full text. Full text is a collection of natural-language documents.

There are two types of text search data types available such as,

• Tsvector-> This data type represents documentation, which is in a form optimized for searching text.
• Query data type text stores the keywords that are needed to be searched.

Date/Time Data types:

The date/ time data type helps the user to store the time zones and dates. By using these data type

You can also change the date/time formats, including traditional PostgreSQL format, ISO 8601, SQL compatibility, etc.

There are six types of Date/Time data types available:

• Timestamp without time zone
• Timestamp with time zone
• Date
• Time without time zone
• Time with time zone
• Interval

Boolean Data types:

There are three types of Boolean data types available,

• True
• False
• Null

Geometric data types:

This Geometric PostgreSQL data type supports two-dimensional spatial objects. By using this data type, we can perform operations like rotations, scaling translation, etc.

There are seven types of Geometric data type available,

• Point
• Line
• Lseg
• Box
• Path
• Polygon
• Circle

Enumerated data types:

Enumerated data types are helpful for the creation of rarely changing information such as Country code or branch ID. This data type helps create a table with foreign keys to ensure data integrity.

Range Data type:

This range data type is used mainly to create many business apps that require data in ranges.

• Int4range
• Int8range
• Numrange
• Tstrange
• Strange
• Date Range

UUID type:

A Universally Unique Identifier (UUID) is the 128-bit quantity used in the generation of an algorithm. This Identifier is mainly used for distributed systems because it provides uniqueness within a single database. UUID is written mainly as a group of lower-case hexadecimal digits, and here, we use hyphens to separate the groups.

XML type:

This XML data type in PostgreSQL allows users to store XML data in data types in the form of extensions. It adds extensions to text data types.

JSON data type:

This JSON PostgreSQL offers 2 data types such as,

• JSON-> a simple extension of text data types with JSON validation
• JSONB-> A binary representation of the JSON data.

Pseudo data types:

PostgreSQL has many notable entries that are called Pseudo-types. But we can't use them as a column-data type. This type is used to declare a function's arguments or return type.

Data tables:

This data type of PostgreSQL is used to create data tables. For example,

• Create
• Delete
• Insert
• Drop
• Alter
• Rename
• Copy

Data Filters:

The key benefit of using this data filter is that it is more readable than the when case statement. Let us get into the brief details,

• Using SQL keyword with the FILTER clause in PostgreSQL
• In this case, we use Filter in a case such that,
• AS
• ANY and ALL
• FROM
• Using the COUNT () ->, this function is used to filter the number of data records when it matches the query.
• One more function we can use here is "CASE WHEN" This is the replacement for PostgreSQL FILTER TYPE.

Data Queries:

This type is used to retrieve the data from the database. In the PostgreSQL query data, type uses the SELECT command to specify the queries.

• SELECT select-list from table…..(insert, delete, create and drop)
• SELECT * FROM table…( used to query the multiple tables)
• Combining queries: this data type is used to combine two or more query results using operations like UNION, INTERSECTIONS, and DIFFERENCE.

Query1 UNION [ALL] query2

Query1 INTERSECT [ALL] query2

Query1 EXCEPT [ALL] query2

PostgreSQL Functions

PostgreSQL function, also known as stored procedures, allows users to perform many operations and queries within the database. This function in PostgreSQL enables the database to reuse other applications.

The basic syntax of this function is as follows,

CREATE [OR REPLACE] FUNCTION function_name (arguments)

…………..

Function totalRecords () syntax is as follows,

CREATE OR REPLACE FUNCTION total records ()

……………

A few of the essential functions we use are,

PostgreSQL COUNT Function

PostgreSQL MAX Function

PostgreSQL MIN Function

PostgreSQL AVG Function

PostgreSQL SUM Function

PostgreSQL ARRAY Function

PostgreSQL NUMERIC Function

PostgreSQL STRING Function

PostgreSQL Applications:

As I said earlier, this PostgreSQL database tool is widely used in many industries. Let us discuss the application of PostgreSQL:

1) Financial Industry:

PostgreSQL database is an ideal tool for financial industries, as it is entirely ACID-compliant and supports the creation of OLTP (online transaction processing). It allows users to work on database analytics. PostgreSQL also offers integration with software like MATLAB and R.

2) Government GIS data:

PostgreSQL database tool offers the most potent GIS applications. They are called "PostGIS". This GIS extension supports thousands of functions that work with geometric data in different available formats.  In recent times, PostGIS has been highly standard-compliant.

In PostgreSQL, we can see two GIS tools, QGIS and Geoserver, which offer the easiest methods to handle Geodata.

3) Manufacturing industry:

Nowadays, many manufacturing industries have started using the PostgreSQL database tool, as it offers a feature that helps speed up their business applications. This PostgreSQL optimizes supply chain management performance. One of the main advantages of using this database tool is that it helps to reduce the cost of business operations.

If you have any doubts about PostgreSQL, then get them clarified by PostgreSQL Industry experts in our PostgreSQL Community!

4) Web development technologies:

Most web development companies prefer PostgreSQL to increase their scalability as they deal with thousands of requests per second at a time. The PostgreSQL tool is the best solution for handling these requests. Many features of PostgreSQL offer the best work experience with modern web frameworks like Node.js, ext.js, and Django.

5) Scientific data:

When you are working on a research and science-related project, it needs to generate terabytes of data. It is essential to handle the data effectively. Data analytics and an effective engine help you to manage a large amount of data with no trouble.

Difference between PostgreSQL and MySQL:

Now it's time to know the difference between PostgreSQL and MySQL.

• PostgreSQL is released under the PostgreSQL License, whereas MySQL is released under the GNU License. 
• PostgreSQL is an open-source software, but Oracle Corp owns MySQL. 
• MySQL is ACID-compliant only at the time of use with engines like NDB and InnoDB. Whereas PostgreSQL is entirely ACID-compliant.
• PostgreSQL works well with complex queries as an excellent DB tool, whereas MySQL works well with OLAP and OLTP apps. 

How to download and install PostgreSQL?

Step-by-step procedure on how to download and install the PostgreSQL tool,

Step 1: First go to the website PostgreSQL Download and select the window as shown in the below figure,

Step 2: Two options available,

• Interactive installer by EnterpriseDB
• Graphic installer by BigSQL
• But BigSQL currently installs pgAdmin version 3, which has been deprecated. So it's better to choose EnterpriseDB, which installs the latest version 4
  
  

Step 3: Now, you will be taken into installing your desired PostgreSQL version and OS. Choose the latest version and OS as per your environment-> click the Download button.

The download will start like this,

Step4: Open the Exe file-> click the next on the install screen

Step 5: Change the installation directory, or if you don't want to leave it to default-> click next

Step 6: Choose the component you want to install; you can uncheck stack builder-> click next

Step 7: you may change the location of data->click next

Step 8: Enter user password -> click next

Step 9: Leave the port number default-> click next

Step 10: Check the pre-installation summary-> click next

Step 11: Click the next button

Step 12: Once the installation is complete, you will see the stack builder,

Uncheck that option -> click finish

Step 13: To launch the PostgreSQL -> got o start menu -> search PgAdmin4

Step 14: Now you get into the PgAdmin homepage

Step 15: Click on the servers-> PostgreSQL 10 in the left tree

Step 16: Enter the user password, which is set during the installation-> click OK

Step 17: Now you will see the Dashboard

Then, it will be taken into the PostgreSQL installation. 

Final Words:

Thus, you have gone through the various concepts of SQL Server DBA and other concepts of SQL Server, Oracle PL/SQL, and PostgreSQL. The SQL server is a popular RDBMS that is highly scalable and helps to store, manage, and recover data requested by various software apps. PostgreSQL is also a free-to-use software and a DBM tool that supports RDBM features. It is a completely customized tool, and there is no cost to buy it. I hope this article will help you acquire updated skills on MS SQL Server, which will help you become a skilled DBA.