SQL is an acronym for Structure Query Language. It is a standard language for manipulating and retrieving data stored in relational databases. In short, SQL lets us communicate with relational databases. With SQL, we can create databases, views, stored procedures, and tables and insert, update, and delete records from a database. 
 

RDBMS stands for a relational database management system, which is a software program for storing, manipulating, querying, and retrieving data from relational databases. Relational databases store only structured data in the form of tables, i.e., rows and columns. They leverage SQL to query data. 
 

Object Models database is a combination of Relational Database and Object Oriented Data Models. These types of databases support the class, objects, inheritance, etc. properties of Object Oriented Modals and Tabular Like structures of Relational Database. 

This type of Database is used with the frameworks of Object-oriented Programming languages. So the developer can write the code in object-oriented programming languages and it can build a database in relational databases. 

Proposed by E.F. Codd in 1969, a relational model is an approach to organizing and managing data in the form of relations called tables. It represents a database as a set of tables or relations, where each relation stores data in tuples (rows) and attributes (columns). 
 

It is obligatory for every database administrator to have a strong understanding of all the database concepts, from the basics to the advanced. Some important database concepts include a database schema, constraint, metadata, instance, query, data engine, and data manipulation. 
 

PostgreSQL, also called Postgres, is a free and open-source relational database management system. It is an object-relational database that has been popular since its inception for its reliability, performance, and reliability. It is available for Windows, macOS servers, FreeBSD, OpenBSD, and Linux. 
 

MySQL is an open-source and free relational database management system. It is also available under a wide range of proprietary licenses. It is compatible with Windows, macOS, FreeBSD, Linux, and Solaris. In addition, it is one of the components of the LAMP (Linux, Apache, MySQL, PHP/Perl/Python) stack. 
 

Oracle or OracleDB is a relational database management system developed and marketed by the Oracle Corporation. It was the first RDBMS designed for data warehousing and enterprise grid computing. It comes in five editions: Enterprise, Standard, Express, Oracle Lite, and Personal. 
 

Microsoft SQL Server, a Microsoft product, is a relational database management system. Along with Oracle and IBM’s DB2, SQL Server is one of the three popular and leading database technologies. It is compatible with Linux, Microsoft Windows, and Windows Server. 
 

MariaDB is a free and open-source relational database management system and is the fork of MySQL. It is available for Windows, Linux, and macOS platforms. In spite of the fact that it is a fork of MySQL, it incorporates features that differ from MySQL. 
 

The installation process of PostgreSQL has been easier than before since the release of PostgreSQL 8.0. This version comes with the installer for Windows to make the installation process quick. To install PostgreSQL on Windows, you need to follow the three simple steps: 

1. Download the PostgreSQL installer for Windows. 
2. Install PostgreSQL.
3. Verify the installation. 
    

To install PostgreSQL on Linux, initially, it is essential for you to choose your Linux distribution and then download the corresponding file. However, on most Linux platforms, PostgreSQL comes integrated with package management.  So, if it is available in package management, install it from there itself. 
 

Docker is a containerization platform for developing, running, and deploying software applications. To use PostgreSQL with Docker, you need to set up a Docker PostgreSQL environment.

You can do this in three simple steps: 

1. Download and install Docker
2. Download Docker PostgreSQL Image
3. Install PGAdmin on Docker
    

There are various server providers on the internet and they all have some steps to configure the PostgreSQL database on their servers. As a Database Administrator, you are also supposed to know how to set up a PostgreSQL database on different servers. 

1. How to Create and Connect PostgreSQL on AWS
2. Setup PostgreSQL on Azure
3. Setup PostgreSQL on Digital Ocean
4. Setup PostgreSQL on Google Clouds

A data type in SQL describes the type of value that you can store in a table column. SQL data types are broadly categorized into the following categories: 

• Numeric
• Date and time
• Character and string
• Unicode character string
• Binary 
• Miscellaneous
   

The data manipulation language (DML) queries are SQL commands for manipulating or modifying data stored in a database. They control access to data and databases. The following is the list of data manipulation language (DML) commands: 

• INSERT: Add new data to a database. 
• UPDATE: Modify existing data in a database. 
• DELETE: Delete specific data from a database. 
   

 
Data Definition Language is the SQL commands that define the database schema. 

Here is a List of DDL commands: 

• CREATE: To create the database
• DROP: To delete the objects from the database.
• ALTER: To alter the structure of the database.
• TRUNCATE: To remove the records from the Database table. 
• RENAME: To Rename the existing table.

There is a single data query language (DQL) command in SQL used for fetching the required data from a database. This command is the SELECT statement. You can leverage the WHERE clause with SELECT to specify conditions for data retrieval.

The data control language (DCL) queries are useful in providing the rights and permissions to users to access databases. There are two DCL commands, namely GRANT and REVOKE. 

• GRANT: Provides users with the access privilege to databases. 
• REVOKE: Takes back the database access privilege from users.  

To use PostgreSQL with Java programs, it is essential to have PostgreSQL JDBC and Java installed and set up on your system. The PostgreSQL JDBC driver will help you use PostgreSQL in your Java programs. 
 

To connect to the PostgreSQL database using Python, you will need to use Psycopg2. Psycopg2 is a PostgreSQL connector library in Python. This library implements the Python DB API 2.0 specification and wraps the libpq PostgreSQL library using the C programming language. 
 

PHP is a scripting language well-known for its faster connectivity with databases. The two popular methods to connect to the PostgreSQL database through PHP are as follows: 
PostgreSQL native functions
PDO (PHP Data Objects)
 

It is pretty simple to use Ruby on Rails with the PostgreSQL database. You need Ruby on Rails and PostgreSQL installed on your system, and by running a few commands, you will be able to use the database with Ruby on Rails applications. 

The ecosystem of Node.js offers an array of tools to connect with databases. To connect with PostgreSQL, it comes with node-postgres containing modules. This tool allows the Node.js interface to communicate with the PostgreSQL database. 
 

Authentication implies an individual trying to log in to a database is authorized or has the right to access the database. 
PostgreSQL makes it easy to manage permissions with the help of roles. Different users can be assigned different roles, and each role has different privileges. For example, a superuser is a role in Postgres with all privileges. 
The PostgreSQL database supports SSL (Secure Socket Layer) connection that allows secure connection with databases. To access databases securely, learn how to enable SSL in PostgreSQL. 
 

In PostgreSQL, whenever an object is created, an owner is assigned to it. For most objects, only their owners can access and modify them initially. However, PostgreSQL allows other users or roles to use or access those objects through privileges or permissions. 
 

SQL injection is one of the most common web hacking approaches that can destroy all data stored in databases. It involves injecting malicious SQL statements through web page input that get executed and destroys databases. 
 

The open-source PostgreSQL database provides a security feature called row-level security. As a database administrator, you will be tasked with leveraging this feature to define security policies on tables so that they can control the viewing and modification of data on a per-user basis. 
 

Data replication is the mechanism of creating multiple copies of data and storing them in different locations. It ensures the high availability of data across a network and no data loss. Even if the data at one location gets lost, its copies are available at different locations. 
 

A backup is generally a copy of data, which safeguards organizations against unexpected data losses. Recovery entails operations for restoring, rolling forward, and rolling back a backup. In short, both backup and recovery involve several operations to protect data stored in databases. 
 

Procedures, often referred to as stored procedures, in DBMS are sub-routines containing a set of SQL statements to be executed to accomplish a specific task. 
 

Connection pooling in a database is an approach to keeping databases open with the intent of reusing them by others. Generally, opening a database connection is an expensive operation. Connection pooling helps in reducing the cost required to create a new connection with a database. 
 

A data cluster is a small group of data that shares common characteristics and significantly differs from other clusters in a database. Cluster management entails a variety of operations, such as node management, configuration management, upgrades, backup management, schema and user management, and private keys and certificates management. 
 

As a database administrator, you must be able to outline a plan for resource usage and management effectively. According to DBA’s resource planning, resources are allocated to each user of a database. 
 

Bash is a shell or command line interpreter for GNU operating systems. It is an acronym for Bourne-Again SHell. More often, as a database administrator, you will be tasked with checking a few details of a database timely, updating or inserting data, or executing a SQL file.  In such cases, you can write a script and automate the execution of SQL files using Bash. 
 

Python is one of the most popular script languages. And with its robust libraries and frameworks, we can easily connect with any relational database. 

1. Python PostgreSQL tutorial
2. How to use MySQL with Python

Data migration is the method of transferring data from one location to another, from one application to another, or from one format to another. In short, it is a method for introducing a new location or system for data. 
 

Understand how to import, export, load, and process data with PostgreSQL. 
Import: Copying data into a database from external files created by exporting from another database. 
Export: Copying data from a database to external files that need to import to another database. 
Load: Copying data into a database from external files that are in any formats supported by a database. 
 

Data partitioning, also sometimes known as data sharding, is the process of distributing large amounts of data across multiple tables, each table holding a small chunk of data called a shard, with the aim of improving query processing performance. 
 

There are four types of processes in the PostgreSQL database: the Postmaster (Daemon) Process, Background Process, Backend Process, and Client Process. 
The PostgreSQL database consists of a memory classified into two different areas, namely the local memory area and the shared memory area. Every backend process allocates itself to the local memory area, while all the processes use the shared memory area. 
 

In PostgreSQL, databases require regular maintenance called vacuuming. The vacuum command processes each table in a PostgreSQL database for various reasons, such as: 

1. Recover or reuse the disk space occupied by deleted or updated rows. 
2. Upgrade data statistics the PostgreSQL query planner leverages. 
3. Update the visibility map. 
4. Protect the old data from getting lost. 
    

In databases, physical storage contains all the files containing data and is independent of logical storage, such as tables, views, and indexes. On the flip side, the file layout in databases is the storage format at the level of files and directories. 
 

For database tables, you can set storage parameters that affect the way the tables are managed in databases. For instance, a storage parameter defines the space and size in which the table should be created. 
 

OLTP is an acronym for Online Transaction Processing. It is a kind of data processing that involves executing transactions that occur concurrently. 
OLAP is the short form for Online Analytical Processing. It is an effective approach to answering multi-dimensional analytical queries in computing. 
HTAP stands for Hybrid Transactional/Analytical Processing. It is the ability of a database to perform OLTP and OLAP for real-time operational intelligence processing. 
 

CTE stands for Common Table Expression. It is simply known as the ‘with’ clause. It returns a temporary data set that you can use in another SQL query. A recursive CTE references itself, i.e., it returns the subset of the result and continuously references itself until it returns the entire result. 
 

As a DBA, you should be familiar with operating systems tools. This is because a database server depends on the operating system of a host computer to provide users with access to resources, such as  CPU, memory, files, and unbuffered I/O disks. Also, it is important to note that every operating system comes with its own utilities to address the usage of system resources. 
 

The pg_stat_statements table contains information about queries that were executed in the past. On the other hand, the pg_stat_activity table entails information about the queries that are currently running. 
 

In the database, query analysis is the process of leveraging SQL statements to determine the ways to optimize queries for better performance. It assists in boosting the overall performance of query processing that speeds up various database functions. 
 

Log analysis is a procedure of analyzing data from log entries and translating it into data that is knowledgeable and usable. This knowledgeable data can be utilized for making business decisions. 
 

USE stands for utilization, saturation, and errors, whereas RED is an acronym for rate, errors, and duration. There are four golden signals, namely latency, traffic, errors, and saturation. All these aspects are ideal for monitoring and troubleshooting database solutions. 
 

A B-tree or multi-way search tree is a tree whose all the leaves are at the same level. It is also referred to as a balanced stored tree. 
In databases, hashing is a process of finding the desired data on the disc without using the index structure. 
GiST is an acronym for Generalized Search Tree. It is a balanced, tree-structured access technique that serves as a basis for the implementation of various arbitrary indexing techniques.
SP-GiST is a short form for space-partitioned GiST. It supports partitioned trees that help in the development of non-balanced data structures. 
GIN is an inverted index, whereas BRIN is Block Range INdexes. 
 

A database schema is generally a formal description of the structure of a database. Only relational databases require to have the schema defined before creating tables. For faster data retrieval, it is essential to choose the optimized schema design pattern. 
 

It is a certification program from Udemy for absolute beginners intended to make them well-versed in PostgreSQL v12. This course will help individuals understand every concept of PostgreSQL and how to install it on Windows and Linux systems. You just need to have a basic understanding of database concepts and working knowledge of Windows and Linux. 
 

Oracle 9i DBA OCA is an entry-level certification issued by Oracle Corporation. It validates individuals for their foundational skills in database administration. One who holds this certification can work as a junior team member with other database administrators in the team. It serves as a prerequisite for many professional-level Oracle DBA certifications. 
 

Oracle9i DBA OCP is a high-level certification that demonstrates individuals’ in-depth knowledge of Oracle database design and implementation skills. Professionals with this certification are capable of designing, developing, and implementing Oracle-based solutions. 
 

MCDBA is a professional who has cleared the certified database certification exam on Microsoft Windows 2000 or 2003, SQL Server Design, Microsoft SQL Server Administration, and the elective approved by Microsoft. However, the Microsoft Certified IT Professional (MCITP) Database certification has replaced MCDBA. 

Professionals holding this certification are in charge of managing the overall Windows Server 2008 R2 environment and architecture. They are also responsible for translating business goals into technology decisions. Also, they make significant decisions regarding the network infrastructure, security policies, business continuity, and many other aspects.
 

For individuals having two to three years of experience working with Windows Server 2008 or any other previous versions, this certification is a perfect choice. It tests applicants’ knowledge of installing, maintaining, monitoring, troubleshooting, and optimizing the performance of Windows Server 2008.