KILLING SESSIONS: In PostgreSQL, you can terminate or “kill” a session using the pg_terminate_backend function. This function allows you to forcefully terminate a specific session, which can be helpful in scenarios where a session is unresponsive or causing issues. We can kill PostgreSQL session in… Read More
Contrib Modules: In PostgreSQL, “contrib” stands for “contributed modules”. These are additional functionalities and features developed by the community that are not part of the core PostgreSQL distribution, but can be easily added to enhance the capabilities of the database. Contributed modules are distributed separately… Read More
Logging mechanism in PostgreSQL: Logging is the process of recording events, actions, and error messages in a systematic manner for future analysis and reference. In PostgreSQL, the logging mechanism helps track various activities like SQL statements executed, connection attempts, query performance, and errors encountered during… Read More
Remote connection from pgadmin4 to a Linux server running PostgreSQL: To establish a remote connection from pgadmin4 to a Linux server running PostgreSQL, Follow the below steps: 1. Install Pgadmin4: First install pgadmin4 on your local machine. You can download it from the official website… Read More
Remote Connections in PostgreSQL: Remote connections will allow you to connect to a PostgreSQL server from a different machine or network. In this article, we will explore the steps to establish remote connections in PostgreSQL and provide best practices for securing these connections. This article… Read More
ENVIRONMENT VARIABLES IN PostgreSQL: These are useful to avoid hard-coding database connection information into simple client applications, for example. To start a PostgreSQL server, you can run the following command:
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[postgres@postgres1 ~]$ /usr/local/pgsql/bin/pg_ctl –D /u01/data start |
However, you can also use an environmental variable to create a shortcut for this… Read More
CLUSTER AND MULTICLUSTERS IN POSTGRESQL: In PostgreSQL Before you can start a PostgreSQL server, you need to create a cluster. A cluster refers to a collection of databases managed by a single instance of the PostgreSQL server. When you install PostgreSQL, It doesn’t automatically create… Read More
Clauses and filters: Like clause:
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college=# select * from report where temp_hi:: text like '4%'; place | temp_lo | temp_hi | date | humidity | precp ----------------------------------------------------------- VZG | 32 | 43 | 2023-05-10 | 21 | HYD | 32 | 43 | 2020-07-19 | 24 | BZA | 32 | 43 | 2023-05-09 | 23 | (3 rows) |
LIMIT Clause: The LIMIT clause is used to restrict the number of rows returned in the result set. It is useful when you want to retrieve only a certain number of rows.
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college=# select * from report LIMIT 4; place | temp_lo | temp_hi | date | humidity | precp ----------------------------------------------------------- VZG | 32 | 43 | 2023-05-10 | 21 | HYD | 32 | 43 | 2020-07-19 | 24 | BZA | 32 | 43 | 2023-05-09 | 23 | Delhi | 23 | 34 | 2023-05-15 | 24 | (4 rows) |
OFFSET Clause: It is used in conjunction… Read More
JOIN OPERATION IN PostgreSQL: In PostgreSQL, the JOIN clause is used to combine rows from two or more tables based on a related column or condition. It specifies how the tables should be joined and on which columns the join should be performed. There are… Read More
CREATING A NEW TABLE You can create a new table by specifying the table name, along with all column names and their types. Syntax for table creation: CREATE TABLE table_name( column1 datatype, column2 datatype, column3 datatype, columnN datatype, PRIMARY KEY (one or more columns) ); An example for creating table on weather… Read More
