It occurs where there is a relationship with partial participation, which forms part of the pathway between entities that are related. Similarly is there any way we can find chasm or fan traps. Bo designer free download as powerpoint presentation. Aug 25, 20 the database mentioned on the website is missing tables and customer service wont reply to email. It can cause numbers to multiply it gives inflated results when u pull data from these tables. The book has a very practical approach towards universe concepts but without the underlying database its useless to buy this book. It does take a structural understanding of the data and more importantly how the user community will consume the data to provide objects to avoid these scenarios. Recognizing and resolving chasm and fan traps when designing universes. Daves adventures in business intelligence fan chasm trap. Part 6 fan trap sap business objects tutorial bobj 4. And yet during this same period unemployment has grown from 420,000 people to 5. Luckily for those of us who deal with data on a daily basis, these traps are a lot less deadly but not by much. A fan trap is solved by creating an alias of the 2nd table and defining contexts such that, the 14.
Fact tables contain measurable business facts like sales or order records and references to dimension tables, which contain details about the entities. Training for analytics with business intelligence bi in. Select the first link draw the diagram of the join as it is seen in the bo designer andsee if there is any fanchasm trap or not. Dec 04, 2019 top business objects interview questions and answers here we have compiled the top sap business objects interview questions and answers to help you in your job interview. The term fan trap helps in one to many joining links which further take action with another one to many joining links. The solution is to adjust your er model like the following shown in only the crows foot notation with the fan trap above and the remodelled version below which resolves the trap. Recognizing and resolving chasm and fan traps when. Interview questions and answers free pdf download page 14 of 51 normal table is joined only with the first table, while the alias is joined with both the 1st and the 3rd table. Rebuild worksheet for fan trap and chasm trap questions. To take a step back, in a denormalized data model, you have fact and dimension tables. The chasm trap occurs when two many to one joins converge on a single table.
A chasm trap occurs when two manytoone joins converge on a single table, and the query includes. A model suggests the existence of a relationship between entity types, but the pathway does not exist between certain entity occurrences. Chasm trap should be solved by making use of two di. Fan trap occur in a situation when a model represents relationship between entity types however a path between certain entity occurrences is ambiguous. This list of interview questions includes the various types of connections, custom hierarchies, schemas supported by business objects designer, data sources and more. Thus, the condition of a chasm trap should be avoidedresolved. Review of the fan trap and chasm trap in entityrelationship diagramming and how to assess whether a potentially redundant connection in an er diagram is in fact required or not. Resolving fan traps in sap bo tutorial 24 april 2020 learn. The fan trap occurs when a one to many join links a table which is in turn linked by. The query information is passed to other system using cwxml common warehouse xml files this makes query data interoperable to desperate systems requiring various different software. Example of how the fantraps and chasm traps works answer abdul. Sap bo interview questions for freshers experienced. This type of join convergence is called a chasm trap.
A chasm trap is a type of join path between three tables when two manytoone joins converge on a single table, and there is no context in place that separates the converging join paths. Select the first link draw the diagram of the join as it is seen in the bo designer andsee if there is any fan chasm trap or not. We are in chasm trap when a table joins with two others in onetomany relationship. A one to many join links to a table which respond with another one to many join links is called fan trap. Top 31 most important sap bo interview questions and answers. The data source or the query is known as the data provider. I tried reading on the following terms but i am still not clear on it.
And why does it strike fear in the hearts of data analysts everywhere. It has the same effect of returning more data than expected. The fan trap is resolved by restructuring the original er model to represent the correct association. A chasm trap occurs when a model suggests the existence of a relationship between entity types, but the pathway does not exist between certain entity occurrences. A chasm trap is simply one specific way that tables in a database schema can be related to one another. Mark ferris this is more because of the order in which you are adding the tables. Resolving fan traps in sap bo resolving fan traps in sap bo courses with reference manuals and examples pdf. It is located in the doorway that leads to the wardens office. It occurs when an er diagram suggests the existence of a relationship between entity sets, but in reality, the connection does not exist. The chasm trap shows you misleading figures in the report which can impact management decision making. We will then notify you when a course has been scheduled. Inflated results are obtained when fields from all 3 tables are included in the query. Nbranch in this model it may be impossible to determine the branch a staff belongs to, in the situation when staff belong to division having more than 1 branches.
This blog post is about describing the fan trap and the chasm trap and how these should be handled in a qlik data model. A chasm trap is a common problem in relational database schemas in which a join path returns more data than expected. I wanted to know how to identify whether your universe contains chasm or fan traps. Go to universe parameters sql multiple paths check the options multiple sql statements for each context and multiple sql statements. However, it also mentioned that the basic solution would not work in most cases, and that contexts would be required for a more complete solution.
The door must be opened through afterlife before the trap can be used. Fan trap the fan trap occurs when a one to many join links a table which is in turn linked by another one to many join. For example a customer can place many ordersand or place many loans. The image on this page were taken in the desktop version of sisense, however, the same principles described on this page also apply to the webbased elasticube manager chasm and fan traps should be avoided when building your elasticube schemas chasm traps. Many to one joins from two fact tables converge on a single lookup table.
A few days ago i finally got started on what will become a series of posts about fan and chasm traps. A chasm occurs when a series of joins crosses a many one a b. There are multiple join paths to go from time entries to clients and hence the prompt. This is the most effective way to solve the fan trap problem. Resolving chasm traps in sap bo tutorial 22 april 2020.
Sep 29, 2014 such a condition is known as a fan trap. Sounds like one of those metal claws hunters put in the jungle to capture leopards and panthers not something you want to fall into around the office. This type of fanning out of one to many joins is called a fan trap. Recognizing and resolving chasm and fan traps when designing. If the question is does designer detect fan traps and chasms automatically the answer is no. Aug 27, 2014 while designing sap businessobjects universe with universe design tool, chasm trap is one of the major join problems that one can come across. Like the below example, general ledger gl is joined with gl balance fact and loan balance fact tables in many ends. Chasm trap is a condition that arises when the values inside the fact table get in. When a one to many join linked by another one to many join in a serious of tables called as fan trap. Reports created on universes having chasm traps tend to give incorrect results. If i were to write a query that spanned all three of those tables the data from table a and c would be duplicated and measure values would be inflated. Hi, there is one pdf document provided by bo, on the traps at this link trap document. How do you go about resolving a chasm trap caused by a many to many relationship in your data where using normal table joins creates a partial cartesian product in tableau.
You should set teh display as the arity in the tooloptions graphics. In fact there are many fan traps that can occur in a universe design that can be ignored as long as you control which types of objects you use. Now you can create the report and it will create separate sql for each context and data will get synchronized based on common dimension customer. Context is formed when the dimension objects are available in one or both fact. The problem i am having is applying conditions at the po distribution level. While designing sap businessobjects universe with universe design tool, chasm trap is one of the major join problems that one can come across we are in chasm trap when a table joins with two others in onetomany relationship. A fan trap simply means you are defining and using measures from two parts of a onetomany join. Free hand sql personal data files stored procedures vb macros olap date formula format date todate,yyyymmdd,ddmmyyyy usersgeneral supervisor supervisor designer supervisor designer user versatile user bca scheduling the reports hourly daily weekly monthly general actions categories scheduling distribution send to bca. As we said,using aggregate awareness we can resolve this issue. Therefore you can actually have a fan trap with only two tables. The query information is passed to other system using cwxml common warehouse xml files this makes query data interoperable to desperate systems requiring various different software landscape. The fan trap occurs when a one to many join links a table which is in turn linked by another one to many join. In bi system fan trap and chasm trap are common problem when designing a universe semantic layer which is used by bi reports to dynamically generate query.
Recognizing and resolving chasm and fan traps when designing universes relational databases can return incorrect results due to limitations in the way that joins are performed in relational databases. According to research business objects has a market share of about 5. Please feel free to register interest for this course on sap training. Boe310 sap businessobjects business intelligence platform. In my universe when i do a integrity check it gives me following result20 1. Scribd is the worlds largest social reading and publishing site. Business object can be considered as integrated analysis, reporting and query for the purpose of finding a solution to some business professionals that can be helpful for them to retrieve data from the corporate databases in a direct manner from the desktop. Resolving chasm traps in tableau tableau community forums. Instead if you had added time entries, expense sheets and then clients, it would know that both of those join paths are required and will not prompt. Chasm traps in universes business one community wiki. Using an alias and the aggregate awareness function. Fan trap occur in a situation when a model represents relationship between entity types however a path between certain entity occurrences is ambiguous example.
There is one pdf document provided by bo, on the traps at this link trap document. Again like chasm trap you have to create two separate queries to display correct result. A fan trap is a less common problem than chasm traps in a relational database schema. Its not because bo is not clever enough, its because a universe developer did not solve traps so heshe tells bo to generate such statements. The database mentioned on the website is missing tables and customer service wont reply to email. A one to many join links a table which is in turn linked by a one to many join. Like in case of loops when we detect loops in the universe it tells us n loops detected. Since bo is creating multiple queries for header and distribution data, the condition on distribution will not be applied to the header query. Fan trap and chasm trap this is an example of fan trap and chasm trap and how to resolve these scenarios. A fan trap occurs in one many many relationship and chasm trap occurs in many one relationship.
A fan trap is a less common problem than chasm traps but has the same effect of returning more data than expected. In france over the past twenty years gnp has grown by 80 per cent, 6 a spectacular performance. This is a join path problem that is created in a universe. With missing tables one cant practice chasm trap, fan trap and other examples in the book. Nbranch in this model it may be impossible to determine the branch a staff belongs to, in the situation when staff belong to division. Apr 16, 2020 best sap bo interview questions and answers. There are lot of opportunities from many reputed companies in the world.
Bca is a software product for the users of webi and bo to process and distribute documents automatically at the scheduled dates and time. Fan trap it occurs when a one to many join links a table which is in turn linked by another one to many join. Unlike loops, which return fewer rows, the chasm and. Top 20 business objects interview questions and answers pdf.
So to answer your question, you can have a wrong sql statement leading to a fan trap results or to a chasm trap results even if you write it in a query tool. The player can evade the fans while they are spinning by crawling under them. Chasm trap and fan traps are the loops which will occur while ditecting loops. Administration and security there are currently no events available for this course. Business objects interview questions and answers business. Creating an alias and applying aggregate awareness function.
A fan trap is a join between 3 tables where a onetomany join links the first table to the second and another onetomany join links the second table to the third. Aug 31, 2014 in bi system fan trap and chasm trap are common problem when designing a universe semantic layer which is used by bi reports to dynamically generate query. The following brief explanation may help you in understanding the concept which is usually found to be dubious across the web. The most common problem caused by a chasm trap is fetching more data than expected. Create two sql statements by checking on the option of multiple sql statements for each measure. Chasm trap the chasm trap occurs when two many to one joins converge on a single table. The best business objects interview questions updated 2020. A fan trap is a type of join path between three tables when a onetomany join links a table which is in turn linked by another onetomany join. I have a fan trap using po header, po lines and po distributions which has been resolved using alias tables. A fan trap is many many relationship 3 or more then three tables are involved. Training for analytics with business intelligence bi in sap. How we will see which trapchasm trap or fantrap was used in. For example when you run a query that asks for the total orders by each order line, for a particular. Resolving fan traps in sap bo tutorial 24 april 2020.