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When you install PostgreSQL, by default connection to the database using TCP/IP is not allowed. When you try to connect from a client to a remote PostgreSQL database using psql command, you might get "psql: could not connect to server: Connection refused" error message. In the following example, from a client machine, we are trying [...]


Most of you are already familiar with SQL database, and have a good knowledge on either MySQL, Oracle, or other SQL databases. In the last several years, NoSQL database is getting widely adopted to solve various business problems. It is helpful to understand the difference between SQL and NoSQL database, and some of available NoSQL [...]


PostgreSQL Trigger Tutorial with EMP Table Examples

Question: I have created triggers in Oracle database. But, I'm new to PostgreSQL. Can you explain me how to create a trigger in Postgres with proper examples? Answer: A trigger can be used to execute a function when an event (insert, or delete, or update) occurs in a table. Let us review how to create [...]


8 PostgreSQL Date and Time Function Examples

In this article, let us review following PostgreSQL date and time functions with practical examples. now() now()::date now()::time date_part() age() extract() date_trunc() to_char() to_timestamp() Get current date and time using the following query. dbase=# select now(); now ------------------------------ 2010-06-19 09:28:43.98216-07 (1 row) Use the ::time as shown below to get only the time (without date). [...]


Question: How do I executed PostgreSQL Commands inside a Linux / UNIX shell script? Answer: With the help of the psql interactive terminal, you can execute the psql commands from the shell script. For this purpose, you should enable the password less login by pg_hba.conf, or .pgpass. psql DBNAME USERNAME << EOF statement 1; statement [...]


15 Advanced PostgreSQL Commands with Examples

Some of the open source application comes with postgreSQL database. To maintain those application, companies may not hire a fulltime postgreSQL DBA. Instead they may request the existing Oracle DBA, or Linux system administrator, or programmers to maintain the potgreSQL. In this article let discuss about the 15 practical postgresql database commands which will be [...]


15 Practical PostgreSQL Database Administration Commands

Earlier we discussed about how to install PostgreSQL database on Linux from source. In this article, let us review top 15 practical postgreSQL DBA command examples. If you are a mySQL administrator, check-out our 15 examples of mysqladmin command article that we discussed a while back. $ /usr/local/pgsql/bin/psql postgres postgres Password: (oldpassword) # ALTER USER [...]


Similar to mySQL, postgreSQL is very famous and feature packed free and open source database. Earlier we've discussed several installations including LAMP stack installation, Apache2 installation from source, PHP5 installation from source and mySQL installation. In this article, let us review how to install postgreSQL database on Linux from source code. From the postgreSQL download [...]