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PostgreSQL Articles
Found 21 articles
How To Configure PostgreSQL 12 Streaming Replication in CentOS 8?
PostgreSQL Streaming Replication continuously streams Write-Ahead Log (WAL) data from a primary (master) node to standby (slave) nodes, creating near-real-time database copies for high availability and fault tolerance. Master Read/Write WAL Slave 1 Slave 2 Read-only Read-only Master Node Configuration 1. Enable WAL Archiving Edit ...
Read MoreHow to Download and Install PostgreSQL on Windows?
PostgreSQL is a powerful, open-source relational database system used for enterprise applications. This guide covers downloading, installing, configuring, and testing PostgreSQL on Windows. Downloading PostgreSQL Go to postgresql.org/download/windows Click Download the installer (EnterpriseDB graphical installer) Select the latest version for your OS (64-bit recommended) Download will begin automatically Installing PostgreSQL Run the downloaded installer and follow these steps − Step 1: Welcome screen → Click Next Step 2: Select components (keep all selected: PostgreSQL Server, pgAdmin, Command Line Tools, Stack Builder) Step 3: Choose installation directory (default recommended) Step 4: Choose data ...
Read MoreHow to Deploy PostgreSQL on Kubernetes?
PostgreSQL is an open-source RDBMS known for handling complex datasets. Kubernetes automates deployment, scaling, and management of containerized applications. Deploying PostgreSQL on Kubernetes provides automated scaling, rolling updates, and improved reliability through replicas and failover. Deployment Steps Cluster Image Manifest Deploy ...
Read MoreHow to Remove Unicode from Jenkins Console Output logs using Postman?
We can remove Unicode from Jenkins Console Output logs. To perform this, we should create a Collection with at least a single request. Along with it, we have to install Newman.Step 1 − Click on the arrow appearing to the right of the name of the Collection. After that, click on Share.Step 2 − SHARE COLLECTION pop-up shall open. Navigate to the Get public link tab and copy the link which is pointed out in the below image.Please note − The link obtained is specific to a particular user.Step 3 − Launch Jenkins and go to the Jenkins Job which ...
Read MoreDifference Between MySQL and PostgreSQL
In this post, we will understand the difference between MySQL and PostgreSQL.MySQLIt is a relational database management system.It is the product developed by Oracle Corporation.It is supported by Windows, Mac OS X, Linux, BSD, UNIX, z/OS, Symbian, AmigaOS.It can’t be extended.In this system, the phpMyAdmin tool gives the GUI.Mysqldump and XtraBackup provide backup in MySQL.It provides temporary table.It doesn’t provide a materialized view.It doesn’t provide Data Domain Object to the system.PostgreSQLIt is an object-relational database management system.It was developed by the Global Development Group.It is supported by Windows, Mac OS X, Linux and BSD but not by UNIX, z/OS, Symbian, ...
Read MoreWhat all constraints can be added to a PostgreSQL table?
There are 6 types of constraints that can be generally used with a PostgreSQL table. They are listed and explained below −NOT NULL CONSTRAINTThis is a very common constraint. If there is a particular column that cannot have null values, you add this constraint at the time of table creation. For example, if we create a marks table, which can’t have NULL values for the name, then the table creation command will look like −CREATE TABLE marks( name VARCHAR NOT NULL, roll_no INTEGER, marks_obtained INTEGER );Now, if we try to insert a row into this table, without ...
Read MoreCreate Primary Key on an existing table in PostgreSQL?
Although quite infrequent, you may come across situations wherein you need to define the primary key on an existing table. This can be achieved using the ALTER TABLE statement.The syntax is −ALTER TABLE table_name ADD PRIMARY KEY (column_name1, column_name2, …., columns_nameN)As can be seen from the above syntax, you can define PRIMARY KEY on multiple columns. When you have defined the PRIMARY KEY on multiple columns, the condition is that the column pairs should have unique and non-null values. Thus, if the PRIMARY KEY is defined on (column1, column2), the values (value1, value2), (value3, value2), and (value1, value4) are allowed. ...
Read MoreExtract day, hour, minute, etc. from a datetime column in PostgreSQL?
Let us create a new table containing a single timestamp column −CREATE TABLE timestamp_test( ts timestamp );Now let us populate it with some data −INSERT INTO timestamp_test(ts) VALUES(current_timestamp), (current_timestamp+interval '5 days'), (current_timestamp-interval '18 hours'), (current_timestamp+interval '1 year'), (current_timestamp+interval '3 minutes'), (current_timestamp-interval '6 years');If you query the table (SELECT * from timestamp_test), you will see the following output −ts2021-01-30 19:23:24.0080872021-02-04 19:23:24.0080872021-01-30 01:23:24.0080872022-01-30 19:23:24.0080872021-01-30 19:26:24.0080872015-01-30 19:23:24.008087Now, in order to extract hour, minute, etc. from the timestamp column, we use the EXTRACT function. Some examples are shown below −SELECT EXTRACT(HOUR from ts) as hour from timestamp_testOutput −hour19191191919Similarly −SELECT EXTRACT(MONTH from ts) as ...
Read MoreHow to combine different columns of a table to yield a single column in query output in PostgreSQL?
Suppose you have a table user_info that contains the state and district of different users. An example is given below −namedistrictstateAnilMumbaiMaharashtraJoyJhalawarRajasthanRonPuneMaharashtraReenaMeerutUttar PradeshNow, if you want to combine the state and district in a single field called location, this is how you should be able to do it −SELECT name, district || ', ' || state as location from user_infoThe || operator is the string concatenation operator. The output will be −namelocationAnilMumbai, MaharashtraJoyJhalawar, RajasthanRonPune, MaharashtraReenaMeerut, Uttar PradeshSimilar operations can also be performed on numerical values. Suppose you have a table marks containing the total marks scored by students and the maximum ...
Read MoreHow to look for partial string matches in queries in PostgreSQL?
Suppose you have a table user_info containing the names of users and their addresses. An example is given below −nameaddressAnilAndheri, Mumbai, MaharashtraJoyChandni Chowk, DelhiRonBandra, Mumbai, MaharashtraReenaOld Airport Road, Bengaluru, KarnatakaNow, if you want to just extract the information of users who stay in Mumbai, you can do that using the LIKE command and the % operator.SELECT * from user_info where address LIKE '%Mumbai%'The output will benameaddressAnilAndheri, Mumbai, MaharashtraRonBandra, Mumbai, MaharashtraNotice that we have added % operator on both sides of Mumbai. This means that anything can precede Mumbai and anything can be after Mumbai. We just want the string to ...
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