Shihab Sikder

howto · 2025-03-14

How to Restart PostgreSQL in Ubuntu 18.04

Learn how to restart PostgreSQL in Ubuntu 18.04 using various methods including terminal commands, systemctl, and pg_ctl. This comprehensive guide provides clear instructions and code examples for efficient PostgreSQL management, ensuring your database runs smoothly. Perfect for beginners and experienced users alike, it enhances your database management skills and helps troubleshoot issues effectively.

howto · 2025-03-14

How to Change the Owner of the PostgreSQL Database

Learn how to change the owner of a PostgreSQL database using the REASSIGN command and other SQL methods. This guide provides clear examples and explanations for transferring ownership of tables and databases, ensuring efficient database management. Discover best practices and avoid common errors in ownership transfer to maintain data integrity.

howto · 2025-03-13

How to Get the Day of a Month in JavaScript

Learn how to get the day of a month in JavaScript using the Date() method and getDate() function. This guide provides clear examples and explanations to help you effectively work with dates in your JavaScript projects. Discover practical applications and enhance your skills with date manipulation today!

howto · 2025-03-13

The $unset Operator in MongoDB

Discover the power of the $unset operator in MongoDB, a crucial tool for deleting fields from your documents. Learn how to use this operator effectively to manage your data, streamline operations, and enhance performance. This comprehensive guide covers practical applications, syntax, and examples to help you master the $unset operator in your MongoDB projects.

howto · 2025-03-13

PostgreSQL Equivalent of SYSDATE

This article discusses the PostgreSQL equivalent of Oracle's SYSDATE. Learn how to use functions like CURRENT_TIMESTAMP, NOW(), LOCALTIMESTAMP, and clock_timestamp() to retrieve the current date and time in PostgreSQL. Discover their unique features and applications to effectively manage time-sensitive data in your database.

howto · 2025-03-11

Postgres Connection String

This article shows the correct format of connection string in Postgres. Learn how to construct secure and efficient Postgres connection strings using environment variables and SSL encryption. Explore practical examples to enhance your database interaction and streamline your development process.

howto · 2025-03-11

How to Check Version of Postgres

This article provides a comprehensive guide on how to check the version of Postgres. Learn various methods, including command line and SQL commands, to easily identify your PostgreSQL version. Stay informed about your database environment and ensure compatibility with applications and features. Whether you're a beginner or an experienced user, this guide offers valuable insights for effective database management.

howto · 2025-03-11

How to Change User Password in Postgres

This tutorial shows how to change the user password in Postgres. Learn different methods, including SQL commands, psql command line, and pgAdmin, to securely manage user passwords in PostgreSQL. Keep your database secure with our easy-to-follow guide.

howto · 2025-03-11

The $ne Operator in MongoDB

Discover the $ne operator in MongoDB, also known as the not equal operator. Learn how to use it effectively in find and update methods with practical examples and clear explanations. Enhance your database querying and manipulation skills with this powerful tool.

howto · 2025-03-11

How to Drop Primary Key in PostgreSQL

This article discusses using the ALTER TABLE query to drop the primary key constraint in PostgreSQL. Learn how to manage your database schema effectively by understanding the implications of dropping primary keys, finding constraint names, and ensuring data integrity. Follow our step-by-step guide to confidently modify your PostgreSQL tables.

howto · 2025-03-11

How to Get Column Names in PostgreSQL

Learn how to get column names in PostgreSQL using two effective methods: the psql command-line interface and SQL queries. This article provides clear explanations and code examples to help you efficiently retrieve column names from your tables. Perfect for developers and database administrators, this guide enhances your PostgreSQL skills and streamlines your database management tasks.

howto · 2025-03-11

How to Search in the Specified Array in MongoDB

Learn how to effectively search in specified arrays in MongoDB using the $in operator. This guide covers simple and nested arrays, providing practical examples and insights to enhance your data querying skills. Discover how to streamline your MongoDB queries and retrieve valuable insights from your data effortlessly.

howto · 2025-03-11

How to Fix AttributeError: 'NoneType' Object Has No Attribute 'Text' in Python

Learn how to fix the AttributeError: 'NoneType' object has no attribute 'text' in Python. This comprehensive guide covers common scenarios that lead to this error, practical solutions, and best practices for error handling. Avoid crashes and improve your coding skills with effective strategies to manage NoneType objects. Perfect for both beginners and experienced developers looking to enhance their Python programming expertise.

howto · 2025-03-11

How to Fix AttributeError: 'Dict' Object Has No Attribute 'Append' in Python

Learn how to fix the AttributeError: 'Dict' object has no attribute 'append' in Python. Discover effective methods such as direct assignment, update(), and setdefault() to add key-value pairs to dictionaries without errors. Enhance your coding skills and avoid common pitfalls with our informative guide.

howto · 2025-03-11

How to Drop if Exists vs Drop in PostgreSQL

Learn the differences between DROP IF EXISTS and DROP in PostgreSQL. This article explores how to safely drop tables, manage foreign key references, and avoid errors. Discover practical examples and best practices for effective database management.

howto · 2025-03-11

How to Print Variable in PostgreSQL

Learn how to print variables in PostgreSQL using the RAISE NOTICE command. This article provides a comprehensive guide on printing simple variables, multiple variables, and conditionally printing information in PL/pgSQL. Enhance your debugging skills and database management efficiency with these essential techniques.

howto · 2024-02-16

How to Use CASE in PostgreSQL

This article shows how to use CASE statement and gives examples in PostgreSQL.

howto · 2024-02-02

How to Change Column Type in Postgres

This article shows how to change the column type to another data type in Postgres.

howto · 2024-02-02

How to Use Database in PostgreSQL

This article demonstrates connecting to a database, creating a new database, and creating a table in PostgreSQL.

howto · 2024-02-02

How to Connect to PostgreSQL With Password

This article shows various methods for connecting PostgreSQL with password. It can be via command-line, pgpass file, PGPASSWORD environment variable or the connection string.

howto · 2024-02-02

How to Query Between Date Ranges in PostgreSQL

In Postgres there're different types of ranges. To compare date you can use the daterange types in you're conditions.

howto · 2024-02-02

How to Query Between Date Ranges in PostgreSQL

In this article, learn the different types of ranges in PostgreSQL. To compare the date, you can use the daterange types in your conditions.

howto · 2024-02-02

How to Use Variables in PostgreSQL

You might need to use variables in PostgreSQL. You can declare your variables using DECLARE in the PL/SQL.

howto · 2024-02-02

How to Use Loop in PostgreSQL

In PL/SQL, you might need to use the loop in Postgres. We can use the FOR and WHILE statements to create a loop.

howto · 2024-02-02

How to Show Connections in PostgreSQL

This article shows how to list active connections on PostgreSQL.

howto · 2024-02-02

How to Run SQL File in PSQL

This article explains how to run a SQL file direct from terminal/command-line or psql shell. For that, you need to specify the hostname, port, username, and database name.

howto · 2024-02-02

How to Left Join Lateral in PostgreSQL

This article is about the left join lateral in PostgreSQL.

howto · 2024-02-02

How to PostgreSQL DATE_TRUNC() Function

Using the DATE_TRUNC() function you can define the precision of datetime in Postgres.

howto · 2024-02-02

How to Update Data in the JSON Field in PostgreSQL

This article discusses how to update a JSON field in Postgres. Using JSONB_SET(), you can modify the existing JSON key-value.

howto · 2024-02-02

How to Find the Disk Size of a PostgreSQL Table and Its Indexes

This article discusses how we can find the disk size of a PostgreSQL table and its indexes. Using the \l+ command, we can show the database sizes, and using \d+, we can view the table sizes.

howto · 2024-02-02

How to Connect to PostgreSQL in SSL Mode

To encrypt the connection between client and the postgres server, we need to use the SSL mode in postgres. As, it's a secure database, to keep it that way we need to use the SSL mode, whenever we're trying to connect via HTTPS.

howto · 2024-02-02

How to Use MongoDB $Pull to Delete Documents Within an Array

Using the $pull we can delete the items inside of an array, where the array resides in the object or document.

howto · 2024-02-02

How to Fix the AttributeError: 'numpy.ndarray' Object Has No Attribute 'Append' in Python

There is no such method called append for NumPy ndarray. The ndarray stands for an n-dimensional array. Rather than calling append() on ndarray, we can call it from a NumPy object.

howto · 2024-02-02

How to Generate a UUID for the Insert Statement in PostgreSQL

UUID is a unique identifier id created by the RFC 4122. There are several versions of it. The latest one is the v4. It's a 32-digit hexadecimal code. We can use it as the primary key.

howto · 2024-02-02

How to Check if a User-Defined Type Already Exists in PostgreSQL

We can use a script to check whether or not the type already exists. Query over the pg_type can inform us whether the user-defined type exists or not.

howto · 2024-02-02

How to Add Primary Key to a PostgreSQL Table Only if It Does Not Exist

Sometimes, we may forget to assign a primary key while executing the CREATE TABLE query. We can use the alter table query to assign the primary key in an existing table.

howto · 2024-02-02

How to Use Where Clause in the Date Field Using PostgreSQL

This article demonstrates the use of where clause in the date type field using PostgreSQL.

howto · 2024-02-02

How to Insert or Update if Exists in PostgreSQL

In Postgres, there's a method called UPSERT which inserts a row if it's not present in the table. Else, it just updates the field of the row.

howto · 2024-02-02

How to Add Days to Date in PostgreSQL

This article illustrates how we can add several days to date while using PostgreSQL.

howto · 2022-07-01

Difference Between deleteMany() and Remove() in MongoDB

Both remove() and deleteMany() deletes data from collection but their input flags and returns are different.

howto · 2022-06-09

JSONB in PostgreSQL

JSONB stands for JSON Binary. Basically a decomposed binary format to store the JSON data. The reason to use this are flexibility in schema, nested object and syncing with exterrrnal data sources.

howto · 2022-05-06

PostgreSQL string_agg Function

This article discusses using the string_agg() function to concatenate strings of a string field in a PostgreSQL group by query.

howto · 2022-04-28

Upsert in MongoDB

Upsert is an option used for the update operation. It takes a boolean parameter and creates a document if there are no matches for the query. You can use it with the update, updateOne, replaceOne, and findAndModify methods.

howto · 2022-03-29

Difference Between Timestamp With and Without Time Zone in PostgreSQL

This article discusses the types of timestamps in PostgreSQL and demonstrates their differences. We can create two types of timestamps in Postgres - with and without a time zone. If you save the timestamp with time zone, you can convert the time into another time zone.