what is an Enterprise Data Model (EDM)?

An enterprise data model (EDM) contains entities, attributes, and relationships that represent the information needs of the entire enterprise.

what is Erwin Data Modeler?

ERwin is a visual data modeling tool that supports logical and physical data modeling.

ERwin is a graphical data modeling tool that allows a modeler to use information requirements and business rules to create a logical and physical data model

defien data warehouse?

A data warehouse is a decisional database system.

It is designed to support the decision makers in the organization in ways a transactional processing system is ill-equipped to handle, such as the strategic-level goals and visions of an organization.

what is oracle warehouse builder?

The Oracle Warehouse Builder (OWB) is a tool provided by Oracle that can be used at every stage of the implementation of a data warehouse right from the initial design and creation of the table structure to ETL and data-quality auditing.

Permanet Journals work along with Backup to make it useful?

True

Permanent Journal tables work along with Archive options.

When DBA archives or backup Permanent journal its current
contents will be deleted

We create a journal / journal table at creation of table?

False.

Journal or Journal table is created at creation time of database
or users. we can also create these using MODIFY statement of
database or user.

At table creation time we just specify
1. Enable or disable journaling for that table
2. which journaling table to be used
3. what type of journaling to be used(Before / After/ Dual Before / Dual After)

what is a permanent journal and explain different types?

A Permanent Journal captures a picture of any row that changes. This would include UPDATES, INSERTS, and DELETES. Permanent Journals do not double the data or PERM for a table, but only doubles the rows that change.

i.e
The Permanent Journal stores only images of rows that have been changed due to an INSERT, UPDATE, or DELETE command.

There are four image options for the Permanent Journal:

· Before Journal

· After Journal

· Dual Before Journal

· Dual After Journal

Create a table with Fall back ,Before Journal and dual after journal features?

create table student ,
fallback,
before journal,
dual after journal
(
sno integer,
sname varchar(30),
sfee decimal(10,2)
)
unique primary index(sno);

what are the different image options for Permanent Journal?

There are four image options for the Permanent Journal:

· Before Journal

· After Journal

· Dual Before Journal

· Dual After Journal

Permanent Journals are automatically purged in teradata. True / False?

False.

The Permanent Journal must be manually purged from time to time.

which objects require Perm space in teradata?

Tables and Stored Procedures objects require Perm Space

Views, Macros , Triggers doesn't require Perm space.

Does Permanent Journals and Secondary indexes require Perm Space?

Ans: Yes

useful URLs?

http://www.coffingdw.com/Teradata_Basics/teradata_basics.htm#chapter_9___advanced_topics_that_you_will_be_tested_on/teradata_cabinets_nodes_vprocs_and_disks.htm

can you list some metrics used in Physical model/ELDM?

Join Access Frequency

Value Access Frequency

Change Rating

Distinct Rows

Max rows NULL, MAX Rows per Value

How do you choose Primary Index for a table in teradata?

A great Primary Index will have:

A Value Access frequency that is high
A Join Access frequency that is high
Reasonable distribution (i.e unique)
A change rating below 2

what is ELDM (Extended Logical Data Modeling) ?

ELDM is very important in terdata data modeling. It comes after Logical modeling
and before physical modeling of database.

1. ELDM is very important and needs extra care. otherwise wrong inputs will go Physical modeling
2.The ELDM will become our final input into the Physical Data Model.
3. In developing Any teradata Physical database, we go through
Logical Design
ELDM
Physical Design
4.The Logical Data Model will be the input to the Extended Logical Data Model.
The Extended Logical Data Model will be input to the Physical Data Model.

5.demographics of data is very important. which we get by questioning logical data modelers

6. Logical data Modeling:
The LDM is a logical representation of tables that reside in the data warehouse database
Once the tables are defined, related, and normalized, the Logical Data Model is complete. Teradata recommends third normal form tables. we can also limit to 2NF

The completed Logical Data Model is used as a basis for the development of the Extended Logical Data Model (EDLM).

7.The ELDM includes information regarding physical column access and data demographics for each table. This also serves as input to the implementation of the Physical Data Model. The ELDM contains demographic information about data distribution, sizing, and access.

The two major components of an ELDM are the following:

COLUMN ACCESS in the WHERE Clause or JOIN CLAUSE.

DATA DEMOGRAPHICS.

8.Physical Database Design portion where we choose our Primary Indexes and Secondary Indexes.

when you may get 10065 WSA E host unreach?

This is mainly because of Firewall on your computer

and we may see this message
C:\Documents and Settings\suresh>pdestate -a
PDE state is RUN/STARTED.
DBS state is 7: System is operational without PEs - Sessions are not allowed

After turning off firewall, if you are still having issue then we may to
bring PE to ONLINE using MULTITOOL.
Once logon to Multitool you may see the following things:

Then we need to set PE state using Tools --> Vproc Manager

Then Vproc Manager opens. then select tab Set Vproc State.


Then set offline PE to online... Now we see





C:\Documents and Settings\suresh>pdestate -a
PDE state is RUN/STARTED.
DBS state is 4: Logons are enabled - Users are logged on

How do you compress tables in teradata?

While creating table we use compress keyword in CREATE TABLE
statement,

we can't compress the following fields

1. Primary Index column
2. Not NULL column

what is a Queue Table?

A queue table is a persistent database table with the properties of an asynchronous
first-in-first-out (FIFO) queue

The queue table is different from a standard base table in that a queue table always contains a user-defined Queue Insertion Timestamp (QITS) as the first column of the table.

Can you expland BYNET?

BYNET Banyan Network (high-speed interconnect)

what is EBCDIC and FIPS ?

EBCDIC Extended Binary Coded Decimal Interchange Code
FIPS Federal Information Processing Standards