The Daily Programming

After installing PostgreSQL, type the following command: $ psql -U postgres postgres is the default super user. We login as Postgresql database system by using this super user.  Display existing user's roles: postgres-# \du+  Create ps_admin role: postgres=# CREATE ROLE ps_admin WITH LOGIN CREATEDB PASSWORD 'admin'; The ps_admin can login with password 'admin' and can create new database. Note: Here, password is simply 'admin'. In the real life the password should be complex combination of words, symbols and numbers. Display list of roles: postgres=# \du+ You will see something like below: Role Name: ps_admin List of roles Attributes: Create DB Create Database: $createdb testdb -p 5432 -h localhost -U ps_admin; The createdb is command line command. The database name testdb will be created under ps_admin user. It should be run in the console. -p = port (default port is 5432) -h = hostname (default hostname is loclhost) -U = username (ps_admin) It will be prom

Sometime we need to convert Output Stream to Input Stream. We can perform the conversion multiple ways.  The following two approaches are most popular: 1. ByteArrayOutputStream to ByteArrayInputStream 2. PipedOutputStream to PipedInputStream Complete example code is available in the [ Github ]. Approach 1: ByteArrayOutputStream/ByteArrayInputStream The ByteArrayOutputStream/ByteArrayInputStream is the easiest way to convert OutputStream to InputStream. Code snippet: TextWriter textWriterBins = new TextWriter(); ByteArrayOutputStream bouts = new ByteArrayOutputStream(); textWriterBins.write(bouts); ByteArrayInputStream bins = new ByteArrayInputStream(bouts.toByteArray()); TextReader textReader = new TextReader(bins); textReader.print(); Here, TextWriter is a class which writes some text in the OutputStream and TextReader is a class which reads data from InputStream and print on the console. In the above code snippet, the TextWriter.write method writes the data in the