PostgreSQL's default command-line interface,psql, offers an efficient way to interact with databases. With its help, you can connect to databases, manipulate data, execute commands, and retrieve results. To list
A function is a good choice to execute an SQL statement that returns a single value result or table formatted result. However, if you want to start a transaction, commit or rollback with multiple SQL statements, then the procedure is the best choice. function PostgreSQL procedure Store Proced...
Example 2: Using JSON_ARRAY_ELEMENTS() Function as a Temp Table The return type of the JSON_ARRAY_ELEMENTS function is “SETOF” which allows us to utilize it as a temporary table. For this purpose, we can execute the JSON_ARRAY_ELEMENTS() function with the “SELECT *” statement as f...
the parsing logic of the two expressions is redirected back to the plpgsql extension throughp_post_columnref_hook. In this context, the post hook function isresolve_column_refinside whichc.idgets resolved.
function main() local conn = db.connect{ api=db.POSTGRES, name='your_odbc_server_name', user='your_login', password='secret', use_unicode = true, live = true } conn:execute{sql='SELECT * FROM <your table>', live=true} end Here, name refers to the name of an ODBC source that...
The next step is to create a trigger and tell it to call this function: 1 2 3 CREATE TRIGGER xtrig BEFORE INSERT ON t_temperature FOR EACH ROW EXECUTE PROCEDURE f_temp(); Our trigger will only fire on INSERT (shortly before it happens). What is also noteworthy here: In PostgreSQL,...
Next we have to bind the trigger function to the table so we will write the following syntax: CREATETRIGGERchange_statusBEFOREUPDATEONproject_statusFOREACHROWEXECUTEPROCEDUREchange_status(); The trigger is created with the name “change_status” and it is specified that the trigger needs to be ...
Option #2: Execute this query to forcefully terminate the backend process: Copy 1SELECTpg_terminate_backend(<pid of the process>); How to rename a database in PostgreSQL? To rename a database in PostgreSQL, you can use theALTER DATABASEstatement followed by theRENAME TOclause. For example,...
The alternative method is to skip using text() and pass a raw SQL string to the .execute() method. For example, here we’ll use .execute() to view the new records we inserted above: with engine.connect() as con: rs = con.execute('SELECT * FROM book') for row in rs: print row...
3.Usually,PostgreSQLstarts automatically on boot up. You can confirm this using the command given below: $ sudo systemctl status postgresql Check PostgreSQL Status 4.To log in to yourPostgreSQLinstance, first switch to thepostgresuser. The Postgres user comes included by default with the installati...