TeraData EXPLAIN Command

The EXPLAIN command is a powerful tool provided with the Teradata database. It is designed to provide an English explanation of what steps the AMP must complete to satisfy the SQL request. The EXPLAIN is based on the PE's execution plan.

The Parsing Engine (PE) does the optimization of the submitted SQL, the creation of the AMP steps and the dispatch to any AMP involved in accessing the data. The EXPLAIN is an SQL modifier; it modifies the way the SQL operates. 

When an SQL statement is submitted using the EXPLAIN, the PE still does the same optimization step as normal. However, instead of building the AMP steps, it builds the English explanation and sends it back to the client software, not to the AMP.

This gives users the ability to see resource utilization, use of indices, and row and time estimates.

TeraData SHOW command

The Teradata Database offers several types of help using an interactive client.

There are times when you need to recreate a table, view, or macro that you already have, or you need to create another object of the same type that is either identical or very similar to an object that is already created. When this is the case, the SHOW command is a way to accomplish what you need. The intent of the SHOW command is to output the CREATE statement that could be used to recreate the object of the type specified.

SHOW TABLE <table-name>; 
Displays the CREATE TABLE statement needed to create this table.

TeraData HELP Command

HELP Command in Teradata plays a important role, This is something like “DESCRIBE” command in Oracle and DB2. This will display the object details.

The HELP Command is used to display information about database objects such as
●     Databases and Users
●     Tables
●     Views
●     Macros

Getting Started with TeraData Vmware

The first task is to make sure you have a system capable of handling VMware and VM’s. There are plenty of details on the VMware site but here are some basic requirements that you should be aware of before getting started:

1. Since the SLES10 VM’s are 64-bit, your CPU must support 64-bit operation.
2. Your CPU must also support Virtualization. Generally there is a BIOS setting which enables this. Google the topic for your particular CPU for more information but most recent PC’s support both 64-bit and Virtualization.