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数据库连接 A string is an expression in which there are all the parameters necessary to establish a connection from a terminal device to a database. It contains databases 用户名 , 密码 , 名称 , 主机地址 and 端口 . This con...

This article will discuss the timestamp types in PostgreSQL and show how they differ. Timestamps in PostgreSQL In PostgreSQL, there are two types of timestamps. Timestamp without time zone Timestamp with time zone The first stores the local...

if Statement evaluates a condition by returning true or false value. We can use it to perform condition based queries. This article will teach you how to write if conditional statements and understand how conditional statements can help you...

This article guides you through using the UPDATE and JOIN statements to update a table. Generate a shipment example in PostgreSQL Consider a store that sells food. Every time a shipment arrives, the price of the product is updated to reflec...

This article will discuss different types of ranges to compare dates in PostgreSQL. Date ranges in PostgreSQL By default, PostgreSQL provides some ranges to compare values. In particular, we can use daterange and between to compare dates. T...

In this article, we will change the user password in Postgres. Changing User Passwords in Postgres Using Windows Open from the menu or search bar SQL Shell (psql) . Connect to the default database using the default port. If you set it up wi...

This article will discuss creating schemas in PostgreSQL using SQL queries or psql. CREATE SCHEMA Use the statement to create a pattern in SQL query To create a new schema, execute the following command. CREATE SCHEMA test_schema To view al...

Today we will learn how to add constraints after the rows in a table have been created UNIQUE . The UNIQUE constraint guarantees that the data in a row is unique in that column. So if the column ID exists, all rows will have unique values,...

Today, we will learn how to kill or stop a running query in the background when working with PostgreSQL database. This may happen if the frontend stops working but a background process is still running. In this case, you may want to kill th...

When working with projects where you need to validate the size of an array or find elements whose size is greater or less than a certain length, you might use MongoDB operators such as $size, $where, $exists, etc. The methods discussed belo...

This MongoDB tutorial article will explain Date() the methods. This article introduces different ways to query using dates. Date() Method in MongoDB Date() The method returns the date as a string or a Date object. In the MongoDB shell or mo...

Sometimes we need to delete data from a database based on specified criteria. Unlike other SQL databases, MongoDB does not include SQL queries for this purpose. Instead, it uses commands. This article will discuss how to delete documents ba...

This article will explain how to delete a user from a MongoDB database. In addition, we will see an example to make the topic easier to understand. Deleting a User from a MongoDB Database Sometimes we need to remove a particular user from t...

This article will introduce various methods of sorting timestamps in MongoDB. Sorting by timestamp in MongoDB sort() The method will sort documents in MongoDB. The method accepts a document containing a list of fields and the order in which...

This short article will cover the various ways to use Compass filters in MongoDB . Compass Filters in MongoDB MongoDB has a GUI called Compass . It is also known as MongoDB GUI. Users can use MongoDB to inspect the contents of their stored...