Answer Posted / ramesh

what is junk dimension? Give an example

When developing a dimensional model, we often encounter miscellaneous flags and indicators. These flags do not logically belong to the core dimension tables.

A junk dimension is grouping of low cardinality flags and indicators. This junk dimension helps in avoiding cluttered design of data warehouse. Provides an easy way to access the dimensions from a single point of entry and improves the performance of sql queries.

Example: For example, assume that there are two dimension tables (gender and marital status). The data of these two tables are shown below:

Code:
Table: Gender
Id Gender_status
----------------
1 Male
2 Female

Table: Marital Status
Id Marital_Status
----------------
1 Single
2 Married
Here both the dimensions have low cardinality flags. This will cause maintenance of two tables and decrease performance of sql queries.

We can combine these two dimensions into a single table by cross joining and can maintain a single dimension table. The result of cross join is shown below:

Code:
id gender mrg_status
--------------------
1 Male Single
2 Male Married
3 Female Single
4 Female Married
This new dimension table is called a junk dimension. This will improve the manageability and improves the sql queries performance.

How are the sources and targets definitions imported in informatica designer?

1170

---

how many types of dimensions are available in informatica?

1176

---

How can we send the flat file data to different targets(which are also flat files) based on the name of flat file with out adding extra columns?

2247

---

What is the commit type if you have a transaction control transformation in the mapping?

1096

---

Define filter transformation?

1147

---

Please let me know how to make encryption and decryption with example?

1946

---

How many ways are there to do 'remove duplicate records in informatica'?

1063

---

What does reusable transformation mean?

1192

---

What are multi-group transformations?

1162

---

Parameter and variable differences

2107

---

What is lookup change?

1108

---

What do mean by local and global repository?

1278

---

what are the different types of transformation available in informatica. And what are the mostly used ones among them?

1139

---

Write the advantages of partitioning a session?

1332

---

What does role playing dimension mean?

1087

---