VenkataRamana_Postgresql_Reference

On Windows First, you need to find the PostgreSQL database directory, it can be something like C:\Program Files\PostgreSQL\10.4\data. Then open Command Prompt and execute this command: pg_ctl -D "C:\Program Files\PostgreSQL\9.6\data" start To stop the server pg_ctl -D "C:\Program Files\PostgreSQL\9.6\data" stop To restart the server: pg_ctl -D "C:\Program Files\PostgreSQL\9.6\data" restart Another way: Open Run Window by Winkey + R Type services.msc Search Postgres service based on version installed. Click stop, start or restart the service option.

While using postgreSQL command line utility " psql " command is giving error like " psql is not recognized as an internal command windows ". To solve this we have to follow below process.  1. Getting the error.  2. Temporary solution for the issue resolution.  3. Updating the " PATH " environment variable for applying the permanent changes.  4. Verifying the fix. Issue solved. 

Below is the process to increase the CMD window. 

Below are the commands for connecting postgresql through CMD.  1. Connecting Postgresql through CMD 3. Existing from Postgresql from CMD.

Below are the commands to get list of DBs in postgresql.

A. Creating Database in Postgresql B. Swithcing between DBs

Below are the statments for Creating table, Inserting in to table and selecting the data. 

Below is the command to get the list of tables in postgresql. 

Below is the process to know the details of the table in PSQL. 

Below is the process to redirect the psql output to a text file.  \o 'D:/temp/Customers_List.txt' SELECT * FROM Tst_ScripFile_Execu_PSQL; \o Please note that once after the query executed, we have to use again "\o" to stop the output redirecting.

Some times we need to execute the script file in PSQL. Below is the procedure to execute the script file in psql.  we have to use command like  \i 'D:/temp/Postgresql_ScriptFile_20191030.sql'

Suppose we are using PSQL (command line tool for postgresql) and want to write an big query like joins and where conditions. Here the problem is, as we are writing the query in command prompt, it will be hard to write big queries.  To solve this problem, we can use psql command " \e ", this command will open the last executed query in notepad file. In this file we can write our lengthy queries, then save the file and close the file. Once after closing the file, psql will execute the query and will provide the result. Here we have to note one thing, that is psql will not show the query that we just write in the notepad file, to check what query executed, we can again use the command " \e ".  Below is the examples of what we have read above. 

1. When we connect Postgresql with particular user, if the user is Superuser or has the privilege Create DB , then the prompt will like " =# " otherwise it will look like " => " .  2. How to write big queries in psql.  https://venkataramanapostgresqlreference.blogspot.com/2019/10/how-write-big-queries-in-psql.html 3. How to execute script file in PSQL. https://venkataramanapostgresqlreference.blogspot.com/2019/10/how-to-execute-script-file-in-psql.html   4. How to redirect the output to a text file in PSQL.  https://venkataramanapostgresqlreference.blogspot.com/2019/10/how-to-redirect-psql-output-to-text-file.html 5. PSQL command to know the details of the table details. https://venkataramanapostgresqlreference.blogspot.com/2019/10/psql-command-to-know-details-of-table.html