Contrast and Resemblances
Contrast and resemblances among Oracle, MySQL and PostgreSQL
Objectives:
  • The main objective of this document is to display the salient features of three database applications, namely , Oracle, MySQL and PostgreSQL.
  • These three databases can be queried using PHP and Java.  
Data Storage:
**~MySQL "database" as a schema/user in Oracle. If you have the privileges, you can query the DBA_USERS view to see the list of schemas

  

Oracle Super User and User with their own tables

The oracle database, renders numerous attributes or properties to each user, and therefore each users is empowered with extensive makeover potentials.

 
PostgreSQL Overview:

  • Server Groups
    • Servers
      • DataBases
        • Database
          • Catalogs
          • Extensions
          • Schemas
            • public
            • Functions
            • Sequences
            • Tables
              • table1
              • table2
              • table n
            • Trigger Functions
            • Views
      • TableSpaces
        • Group Roles
      • login roles

 
PostgreSQL : Can hold more than one server , pgaAdmin3.exe uploads the links for both the servers.

object hierarchies in postgresql

 
MYSQL :

Made of database schemas

MyISAM The default non-transactional storage engine that with full-text indexing.It is highly portable, stores data in stores data in .FRM, .MYD and .MYI files.
MERGE A non-transactional storage engine that allows a collection of MyISAM tables with identical column and index information to be used as one
MEMORY (HEAP) A non-transactional storage engine that stores data in memory
BDB (Berkeley DB) The first transactional-safe storage engine
InnoDB This has a transactional-safe storage engine designed for maximum performance,row-level locking, and  stores data in a common tablespace or individual tablespaces per table.
FEDERATED A storage engine that accesses data in tables of remote databases rather than in local tables
ARCHIVE This storage engine that can store large amount of data without indexes in very small footprint.
CSV A storage engine that stores data in text file using comma-separated-values format
BLACKHOLE A temporary storage engine that acts as a "black hole" that accepts data but won't store and would discard the data later on.
EXAMPLE A "stub" engine that does nothing. Its purpose is to serve as an example that illustrates how to begin writing new engines.
ISAM The original MySQL storage engine that has been deprecated in favor of the MyISAM storage engine as of version 5.0

Now let us use MySQL Workbench, note list of schemas in the database.
It is two early 
<?php
//$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
$mysqli = new mysqli("Manas9", "Manas9", "Manas9237", "test");
/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$query  = "SELECT CURRENT_USER();";
$query .= "SELECT fname, lname FROM emp1 ORDER BY fname";

/* execute multi query */
if ($mysqli->multi_query($query)) {
   do{
        /* store first result set */
        if ($result = $mysqli->use_result()) {
            while ($row = $result->fetch_row()) {
               echo("<br/>". $row[0]."&nbsp". $row[1]);
            }
            $result->close();
        }

    }  while ($mysqli->next_result());
}

/* close connection */
$mysqli->close();
?>

 
phpMyAdmin much more users friendly and

Now use Browse menu to view the table

You may also use php script, order of data display was different, than the  logical view, due a filter "order by fname" in the selection query.