Skip to main content

Difference b/w Logical join and Physical Join in OBIEE 11g

By


1. Relationship between the logical tables was expressed by logical joins in BMM layer.

2. Logical joins express the cardinality relationships between logical tables and are a requirement for a valid business model. 

3. Specifying the logical table joins is required so that Oracle BI Server can have the necessary metadata to translate logical requests against the business model into SQL queries against the physical data sources. Logical joins help Oracle BI Server understand the relationships between the various pieces of the business model. 

4. When a query is sent to Oracle BI Server, the server figures out how to construct physical queries by examining how the logical model is structured. 

5. Examining logical joins is an integral part of this process. 

6. The Administration Tool considers a table to be a logical fact table if it is at the “many” end of all logical joins that connect it to other logical tables.

Physical Joins

1. Relationship between the physical tables and columns are expressed by physical join in the physical layer.

2. A primary key and foreign key relationship defines a one-to-many relationship between two tables. 

3. A foreign key is a column or a set of columns in one table that references the primary key columns in another table. 

4. The primary key is defined as a column or set of columns where each value is unique and identifies a single row of the table. 

5. Keys and joins help Oracle BI Server determine the fact–dimension relationships between tables.

6. The Physical layer typically uses foreign key joins to define relationships, whereas the Business Model and Mapping layer uses logical joins to define relationships.

Labels

Labels:

Comments

Post a Comment

Popular posts from this blog

Contact Me

By
Do You have any queries ?                   If you are having any query or wishing to get any type of help related Datawarehouse, OBIEE, OBIA, OAC then please e-email on below. I will reply to your email within 24 hrs. If I didn’t reply to you within 24 Hrs., Please be patience, I must be busy in some work. kashif7222@gmail.com
3 comments
Read more

Top 100 Informatica Interview Questions

By
I have attended Informatica interview last week in wipro and couple of other companies, Question below I faced in those companies. 1. What are the main issues while working with flat files as source and as targets ? 2. Explain about Informatica server process that how it works relates to mapping variables? 3. write a query to retrieve the latest records from the table sorted by version(scd) 4. How do you handle two sessions in Informatica 5. which one is better performance wise joiner or look up 6. How to partition the Session? 7. How many types of sessions are there in informatica.please explain them. 8. Explain the pipeline partition with real time example? 9. Explain about cumulative Sum or moving sum? 10. CONVERT MULTIPLE ROWS TO SINGLE ROW (MULTIPLE COLUMNS) IN INFORMATICA 11. DEPLOYMENT GROUPS IN INFORMATICA 12. LOAD LAST N RECORDS OF FILE INTO TARGET TABLE - INFORMATICA 13. LOAD ALTERNATIVE RECORDS / ROWS INTO...
129 comments
Read more

Top 130 SQL Interview Questions And Answers

By
1. Display the dept information from department table.   Select   *   from   dept; 2. Display the details of all employees   Select * from emp; 3. Display the name and job for all employees    Select ename ,job from emp; 4. Display name and salary for all employees.   Select ename   , sal   from emp;   5. Display employee number and total salary   for each employee. Select empno, sal+comm from emp; 6. Display employee name and annual salary for all employees.   Select empno,empname,12*sal+nvl(comm,0) annualsal from emp; 7. Display the names of all employees who are working in department number 10   Select ename from emp where deptno=10; 8. Display the names of all employees working as   clerks and drawing a salary more than 3000   Select ename from emp where job=’clerk’and sal>3000; 9. Display employee number and names for employees who earn commissi...
32 comments
Read more