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SAP Business Objects Universe Designer Interview Questions – Scenario Based

What is loop in Universe? Explain its problem and different methodologies to resolve it.

Loops occur when there are two different paths to accomplish one join. The following structure now includes PRODUCT_PROMOTION_FACTS in the Test Fashion universe. If users want to analyze articles versus time, there are now two join paths. Business Objects does not know which path to take, the one via SHOP_FACTS or the one via PRODUCT_PROMOTION_FACTS.

The circular appearance of these four joins is a loop, which can give undesired SQL results.

One way of spotting the problem table in the loop is the table which has at one end of the one-to-many relationship.

If loops are not resolved and report is run following error might come.

Error: Incompatible combination of objects

There are different methodologies to resolve loops depending on the type of loop.

Contexts

Context is simply a list of joins that defines a specific path for query.

It breaks loop by defining set of joins that define path through table in a loop.

It ensures that joins are not included from different path within the same sql.

If object from two different contexts are used in report. BO generates two different SQL.

Dis-advantage:
When you use a context, you expose the BO end user to the database structure. They are forced to decide which context they want to use to run their query. The role of the universe is to shield end users from the database structure, so they do not have to make such decisions.

To test the contexts:

Create a query which includes objects which are only in one context : BO should be able to get the correct result by determining the context.

Create a query which includes objects from both the contexts. BO should generate two queries and then unions it.

Create a query which includes object which are common two both the context. BO should prompt for contexts to be used.

Designer detects context by identifying table which has only many ends of joins attached. No joins following back from one to many are included.

Every Join except shortcut join must exist in at least one context.


Alias

Alias breaks the loop by using same table with different name in the query.

In above example we can create the alias for calendar_year_lookup table.

Original table would join to shop facts and alias will join to promotion fact which would break the loop.

However you would need to define the object based on there meaning.

e.g. to get the shopping month you can use original table whereas to get the promotion month you need to use alias table.

What is CHASM trap and how to resolve it

Fan traps and Chasm traps are problems in which are inherent in SQL that are caused by the order in which the elements of SELECT are processed.

In SQL a select statement processes SELECT, FROM and WHERE cause first and forms a result table in memory based on the tables specified in where clause and restrictions specified. However this does not cause a problem, but if aggregates are applied then it may cause a problem in particular circumstances.

These traps are difficult to identify unless you take a deeper look at the detailed data.

These traps return many row than expected.

Chasm trap is a common problem in relational database in which a join path returns more data than expected.

A chasm trap is a join path between three tables when two many-to-one join path converge on a single table and there is no context in place that separates the converging path.

You only get incorrect result in following situations.

There is many-to-one-to-many relationship between three table in universe.

The query includes objects based on the two “many” tables

There are multiple row returned for single dimension.

For example in above diagram there is no loop, but the flow around three table is many-to-one-many.

When a query that uses objects Y and Z is run, the inferred SQL includes tables B,C,A that have a many-to-one-many relationship. The chasm traps causes a query to return every possible combinations of one measure with every possible combination of another measure. The results in the values for each objects being multiplied by other. The effect is similar to a Cartesian product but known as CHASM trap.

CHASM trap is resolved by executing separate statement for Y and Z and combining the result.

Note: the chasm trap is not dependent on object type. Y and Z can be dimension

Detecting CHASM trap.

Unlike loops chasm traps are not detected automatically by designer. Need to detect manually.

Analyze the one to many relationship join paths in schema to detect CHASM trap graphically.

Analyze the proposed detected to separate the queries for such join paths.

Add additional dimension or detail objects to display more information in the report . If there is chasm trap aggregated value wil be doubled alerting you a chasm trap.

Now if you run query with client name and sale revenue or rental revenue. You would see correct result. However you want to see client name with sale and client revenue you would end up getting wrong result.

Suppose Sale revenue is 2000 and rental revenue is 4000 for client Kumar. You would see result as

Client Name    Sale revenue  Rental Revenue

Kumar              4000                 8000

This is because of chasm trap.

Internally it is bringing result as micrcocube

Client Name    Sale revenue  Rental Revenue

Kumar              2000                 4000

Kumar              2000                 4000

And while projecting this data in report BO aggregates it to client name and shows wrong result.

Resolving CHASM trap.

Modify SQL parameters of the universe and click generate separate queries for measures. However this works with measures and might result in inefficient queries and does not works with dimensions.

Create a contexts for each fact. This solution works well and recommended.

When you create context and two entities from separte context are used in SQL. BO generates separate queries regardless of measure/dimension. Which solves this trap problem

When any new universe changes are deployed how does the end user get the view of the new classes/objects added(apart from specs doc)?

when universe get changed, we do export the changed universe to enterprise server. user gets the view of changed classes objects what ever we done at universe and already existed objects which are not changed are viewed as same like before.

I have 2 universes. that is u1 and u2. From u1,i created one report that is r1. Now i want to give the connection r1 to u2 and at the same time delete the connection from u1 to r1 ? How is it possible explain?

can change the connection for the report r1.For webI reports in query panel on left side we have query properties there we can change the connection of the universe to u2.then it will map to the u2.

What is meant by ZABO and FC(full-client)?

This module of the application is hybrid of the thin client and the Full Client Modules of Business Objects Reporting Module. ZABO stands for Zero Administration BusinessObjects. This application uses the hardware resources of the client machine for application level processing and communicates through the protocol defined for the browser to use the server resources for processing External requests (like running a database Query, creating a data provider to access data.)

ZABO means Zero Administration Business Objects and this is 3-tier level architecture.

No need to install any BO software.

Full Client means 2 -tier level architecture we can directly connect to repository only we defines key file and this Fullclient we need BO tools our local system also.

what happens if cardinalities are not resolved?

If Cardinalities are not specified between the tables i.e the relationship between the tables ( 1-1,1-MANY,MANY-MANY)

We get more results at report level more than the actual result,like a Cartesian product.

We can’t detect the Loops & Traps (Chasam & Fan) Which are mainly detected by the

CARDINALITIES option

What is aggregate navigation.

Aggregate Navigation is used to specify the incompatible  objects.

Whenever we use Aggregate Aware we need to set up  incompatilibities to work it properly (so BusinessObjects  knows what SQL to generate)

For example, There are 2 aggregate tables fact table by

week and by day.If you set up a measure as aggregate aware  from both tables – total quantity for example, the select  might be something like: –

@Aggregate_Aware(sum(week_agg.qty),sum(day_agg.qty))

The week table listed first as this would be the  preference. But as BusinessObjects needs a reason to not go  to the week_agg table, this is done using  incompatibilities. For example the Week Number dimension  object would be compatible with the week_agg table as it  will link to it and the data is held at an appropriate  level to report against it. However the Date dimension  object would be set as incompatible with the week_agg  table, such that when it is selected alongside the Quantity  object, BusinessObjects knows to jump to the next option in  its select definition.

What is Index Awareness in Universe.

Index awareness is the ability to take advantage of the indexes on key column to speed data retrieval.

The objects that you create in the universe are based on database columns that are meaningful to an end user. For example, a customer objects retrives the fields that contains name. In this situation the customer table typically has primary key (e.g. in integer) that is not meaningful to the end user, but which is very useful for DB performance. When you set up index awareness in designer, you tell designer which database columns are primary and foreign keys. This can have dramatic effect on query performance in the following ways.

Designer Can take advantage of the indexes on key columns to speed up data retrieval

Designer can generate SQL that filters in the most efficient way. This is particularly more important in a start schema . If you build a query that involves filtering on a value from dimension table. Designer can apply the filter directly on the fact table using table foreign  key. This eliminates unnecessary joins to dimensions tables.

Designer does not ignore duplicates with index awareness. If two customers have same name. Designer retrieves only one unless it is aware that each customer has a separate primary key.

To setup index awareness open the properties of objects, open “Keys” tab. Click insert and add respective PK and FK.

What are @functions

@Aggregate_Aware (2) @Prompt (3) @Script (4) @Select (5) @Variable (6) @Where

@Prompt: message prompts the end user to enter a specific value.

Syntax: @Prompt (‘message’, [‘type’], [lov], [MONO|MULTI], [FREE|CONSTRAINED])

@Script: This function recovers the results of Visual Basic for Applications macro (VBA macro).
Syntax: @Script (‘var_name’, ‘vartype’, ‘script_name’)

@Select: This function enables you to re-use the Select statement of an existing object.
Syntax: @Select (Classname\Objectname)

@Variable: The @Variable is used to reference the value assigned to a name or variable.
Syntax: @Variable(‘myname’)

@Where: This function lets you re-use the Where clause of an existing object.
Syntax: @Where (Classname\Objectname)

What is core Universe

The core universe is a universe to which other universes are linked. It contains

components that are common to the other universes linking to it. These

universes are called derived universes.The core universe represents a

re-usable library of components.

A core universe can be a kernel or master universe depending on the way the core universe components are used in the derived universes.

What is derived universe.

A derived universe is a universe that contains a link to a core universe. The

link allows the derived universe to share common components of the core

universe:

• If the linked core universe is a kernal universe, then components can be

added to the derived universe.

• If the linked core universe is a master universe, then the derived universe

contains all the core universe components. Classes and objects are not added to the derived universe. They can be hidden in the derived universe depending on the user needs of the target audience.

What are linked universes? Explain with advantages and disadvantages.

Linked universes are universes that share common components such as parameters, classes, objects, or joins. Among linked universes, one universe is said to be the kernel or master while the others are the derived universes.A kernel or master universe represents a re-useable library of components.

Derived universes may contain some or all of the components of the kernel or master universe, in addition to any components that have been added to it.

You have the following advantages when linking universes:

• Reduce development and maintenance time. When you modify a component in the core universe, Designer propagates the change to the same component in all the derived universes.

• You can centralize often used components in a core universe, and then include them in all new universes. You do not have to re-create common components each time you create a new universe.

• Facilitate specialization. Development can be split between database administrators who set up a basic core universe, and the more specialized designers who create more functional universes based on their specific field.

Requirements for linking universes

You can link the active universe to a core universe, only if the following requirements are met:

The core universe and derived universe use the same data account, or database, and the same RDBMS. Using the same connection for both the core and the derived universe makes managing the universes easier, but this can be changed at any time.

• The core and derived universes must be in the same repository.

• The core universe was exported and re-imported at least once. The derived

universe does not need to have been exported before creating a link.

• Exported derived universes are located in the same universe domain as

the core universe.

• You are authorized to link the given universe.

Restrictions when linking universes

You need to be aware of the following restrictions when linking universes:

• You cannot link to a universe that uses stored procedures.

• You can use only one level of linking. You cannot create derived universes from a universe which is itself derived.

• All classes and objects are unique in both the core universe and the derived universes. If not conflicts will occur.

• The two universe structures must allow joins to be created between a table in one universe to a table in the other universe. If not, then Cartesian products can result when a query is run with objects from both structures.

• Only the table schema, classes and objects of the core universe are available in the derived universe. Contexts must be re-detected in the derived universe.

• Lists of values associated with a core universe are not saved when you export a derived universe with the core universe structures.

Creating a link between two universes

You can link an active universe to another universe. When you do so, the active universe becomes the derived universe, and the linked universe becomes the core universe. Components from the core universe are inherited by the derived universe.

To link a universe to a core universe, the core universe must have been

exported to the repository.

Note: When you link universes, you can relocate the core universe within the same repository with out breaking the link. This allows you to export the core universe to a different repository folder, while keeping the links with derived universes valid.

What is Object Qualification

For the purposes of multidimensional analysis, objects are qualified as one of three types: dimension, detail, or measure.

How to create filter in Universe and what is advantages and disadvantages.

A condition object is a predefined Where clause that can be inserted into the Select statement inferred by objects in the Query pane.

Condition objects are stored in the Conditions view of the Universe pane. You access the conditions view by clicking the Conditions radio button at the right bottom of the universe pane

Using condition objects has the following advantages:

• Useful for complex or frequently used conditions.

• Gives users the choice of applying the condition.

• No need for multiple objects.  Building universes Defining objects

• Condition objects do not change the view of the classes and objects in the Universe pane.

Note: You may need to direct users to use the condition objects view of the Universe pane. The only disadvantages for using condition objects is that you may want to force a condition on users to restrict their access to part of the data set. In this case you need to define a Where clause in the object definition.

Why do we need to create derived table in Universe.

Sometimes it not possible to create dimension/measure directly in universe in that case we use derived tables. E.g. First time users, union queries etc.

Explain security level in BO Universe

Defines the security access level of the object.You can select a security level which restricts use of the object to users with the appropriate security level. You can assign the following security access levels:

• Public

• Controlled

• Restricted

• Confidential

• Private

If you assign Public then all users can see and use the object. If you assign Restricted, hen only users with the user profile of Restricted or higher can see and use the object.

How to implement row level security in Universe.

You can define a WHERE clause that restricts access to row and limits the result set returned by a query.

To create restrictions Select Tools > Manage Security > Manage Access Restrictions and click rows


How do you determine when to use alias and when to use context.

There is no strict rule to follow for resolving loops. However, whenever possible you should use an alias instead of a context. When you use a context, you expose the BUSINESSOBJECTS end user to the database structure. They are forced to decide which context they want to use to run their query. The role of the universe is to shield end users from the database structure, so they do not have to make such decisions.

Contexts can be confusing for end users

A context can be confusing for end users when they are forced to make a decision about the meaning of an object. For example an object called Country can have several meanings; the customer’s country of residence, the shipment destination, or the product’s country of manufacture. When you run a query in BUSINESSOBJECTS or WEBINTELLIGENCE, you are also asked to indicate the correct database path to follow.

Deciding to use an alias or context

You can use the following rules to help you decide whether an alias or context is appropriate for resolving loops: When you create aliases and you end up with object names that sound very different (Customer’s Country of Residence, Shipment Destination, and Products Country of Manufacture), aliases are probably the right solution.

If you end up with object names that sound very similar (such as Ordered Products and Loaned Products as well as Ordered Products’ Country of Manufacture and Loaned Products’ Country of Manufacture), you should consider using contexts.

What are different ways to link universes.

You can use any the following approaches when linking universes:

• Kernel approach

• Master approach

• Component approach

You can use any of the three approaches individually, or, combine one

or more together.

Kernel approach

With the kernel approach, one universe contains the core components. These are the components common in all universes. The derived universes that you create from this kernel universe contain these core components as well as their own specific components.

In the example below, the universes Human Resources and Sales are derived from a kernel universe. They contain core components of the kernel universe as well as their own specific components.

Any changes you make to the kernel universe are automatically reflected in the core components of all the derived universes.

Master approach

The master approach is another way of organizing the common components of linked universes.

The master universe holds all possible components. In the universes derived from the master, certain components are hidden depending on their relevance to the target users of the derived universe.

The components visible in the derived universes are always a subset of the master universe. There are no new components added specific to the derived universe. The example below shows the universes Human Resources and Sales are derived from a master universe. They contain components from the master universe, some of which may be hidden. Any changes you make to the master universe are automatically reflected in the core components of all the derived universes.

Component approach

The component approach involves merging two or more universes into one universe. The Sales universe below was created by merging two universes: Part 1 and Part 2.

How do you distribute Universe?

Designer allows you to distribute universes by importing and exporting universes to the Central Management System (CMS) repository.

What is the list mode?

List Mode provides list of all the tables, joins, and contexts.àList mode command View

What is Parse checking?

Parse checking means how DESIGNER is to determine the validity of an object, join, or condition.
• Quick parsing checks only the syntax of components.
• Thorough parsing checks both the syntax and semantics of components.

If there are changes in the database on which you have already created a universe, how do you include those additional changes into your universe?

By refreshing the structure I get the updated database structure.

What is the difference between linking and including the universes?

• Linking a universe is a process, which includes the required objects/classes of the master on to the derived universe. But any change made to the master universe is reflected onto the derived universe.
• Including a universe creates all the required objects from the master universe on to the derived universe; any change made to the master universe does not impact the derived universe.

What is a list of values?

A list of values contains the data values associated with an object. These data values can originate from a corporate database, or a flat file such as a text file or Excel file. In Designer you create a list of values by running a query from the Query Panel. You can then view, edit, purge, refresh, and even export this file. A list of values is stored as an .lov file in a subfolder of the UserDocs folder.

What are the requirements for linking universes

You can link the active universe to a kernel universe, only if the following requirements are met:

The kernel universe and active universe were created from the same data account and the same RDBMS.

The kernel universe was exported and re-imported at least once.

Exported derived universes are located in the same universe domain as the kernel universe.

All classes and objects are unique in both the kernel universe and the derived universes. (Otherwise, collisions may occur.)You are authorized to link the given universe.

Note:

A derived universe does not recover the lists of values containing personal data from the kernel universe. However, if you need certain lists of values, you can use the following workaround: in the derived universe, create new objects defined in the same way as those in the kernel, then hide them. You can then assign them to these objects lists of values, which you can then modify and export.

How to create hierarchies in BO?

A hierarchy, which the designer sets up when creating the universe, consists of dimension objects ranked from “less detailed” to “more detailed”. The objects that belong to hierarchies are the ones you can use to define scope of analysis.

Creating hierarchies

You can create your own custom hierarchies from any dimensions available in

the report. The dimensions you include in a hierarchy can be local variables,

derived variables, or dimensions returned by data providers.

Note: You can also use a date-type user object as the basis for a time hierarchy.

For information on user objects see “Creating User Objects” on page 78.

To create a custom hierarchy

1. Click the Hierarchies command on the Analysis menu.

The Hierarchy Editor opens.

2. In the Hierarchy Editor, click New.

3. Type the name of the new hierarchy, then click outside the name box.

4. In the Available Dimensions box, click the first dimension for the new

hierarchy, then click Add.

The dimension you clicked appears in the new hierarchy’s folder in the

Available Hierarchies box.

Add the other dimensions you want to include and then click OK.

What are the disadvantages of Alias?

Aliases will create complex in structure of the Universe

What are linked Universes

Linked universes are universes that share common components such as parameters, classes, objects, or joins. Among linked universes, one universe is said to be the kernel or master universe while the others are the derived universes.

A kernel or master universe represents a re-usable library of components. Derived universes may contain some or all the components of the kernel or master universe, in addition to any components that have been added to it.

Approaches to linking universes

You can use one of three approaches when linking universes:

• The kernel approach

• The master approach

• The component approach

The Benefits of Linked Universes

You have the following advantages when linking universes:

• Reduce development and maintenance time. When you modify a component in the core universe, Designer propagates the change to the same component in all the derived universes.

• You can centralize often used components in a core universe, and then include them in all new universes. You do not have to re-create common components each time you create a new universe.

• Facilitate specialization. Development can be split between database administrators who set up a basic core universe, and the more specialized designers who create more functional universes based on their specific field.

Requirements for linking universes

You can link the active universe to a kernel universe, only if the following requirements are met:

The kernel universe and active universe were created from the same data account and the same RDBMS.

The kernel universe was exported and re-imported at least once.

Exported derived universes are located in the same universe domain as the kernel universe.

All classes and objects are unique in both the kernel universe and the derived universes. (Otherwise, collisions may occur.)

You are authorized to link the given universe.

Note: A derived universe does not recover the lists of values containing personal data from the kernel universe. However, if you need certain lists of values, you can use the following workaround: in the derived universe, create new objects defined in the same way as those in the kernel, then hide them. You can then assign them to these objects lists of values, which you can then modify and export.

Explain Universe Design Methodology.

The universe design methodology described in this manual consists of one planning stage, and three implementation phases:

Analysis of business problem and planning the universe solution

Designing a schema

Building the universe

Distributing the universe to users

Each implementation phase is based on an assumption that you have completed an initial planning phase. The planning phase can be done without using Designer, and is the decisive phase for the success or failure of your universe. A poorly planned universe that is not based on a study of user reporting needs will be difficult to design, implement, maintain, and will not be useful to your target users. Each of these phases is described as follows:

Plan the universe before you start using Designer

Before starting the first phase, you should spend up to eighty percent of the time allotted for the universe creation project, planning the universe. You should note the following points:

• You must analyze the data analysis and reporting needs of the target audience for the universe. The structures that you use to create the schema should be based on a clearly defined user need to access the data contained in those tables and columns.

• You should have a clear idea of the objects that you need to create before you start using Designer. Do not create objects by looking at the columns available in the database, but identify columns that match an object that you have already identified from your user needs analysis.

Designing a schema

You create a schema for the underlying database structure of your universe. This schema includes the tables and columns of the target database and the joins by which they are linked. You may need to resolve join problems such as loops, chasm traps, and fan traps, which may occur in the structure by using aliases or contexts. You test the integrity of the overall structure.

Building the universe

You create the objects that infer Select statements based on the components of your schema. You organize these objects into classes. These are objects that you have identified from an analysis of user reporting needs. You can create many types of objects to enhance user reporting capabilities, multidimensional analysis, and optimize query performance. You test the integrity of your universe structure. You should also perform tests by running reports in Web Intelligence.

Distributing the universe

You can distribute your universes to users for testing, and eventually for production, by exporting them to the Crystal Management System (CMS) repository.

Explain Universe Development Lifecycle.

Universe development is a cyclic process which includes planning, designing, building, distribution, and maintenance phases. You use Designer to design and build a universe, however, the usability of any universe is directly related to how successfully the other phases in the development cycle interact with

each other.

This section presents an overview of a universe design methodology that you can use to plan and implement a universe development project. The table below outlines the major phases in a typical universe development cycle:

Prepare %3

One can always prepare best by reading books here are few on BO

 


Universe Access Restriction

Once you are done with development of universe there might be requirement to restrict the universe access to particular user or user group. You can achieve this by applying various access restrictions in universe.

Universe has various types of access restriction as explained below.

Connection: Using this access restriction you can define which connection is accessible to which user group.

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SQL Controls: Using the restriction type one can define result set size and query execution time.

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SQL: Using this restriction you control the SQL generation.

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Objects: Using this restriction you can define which objects will be not be accessible to which users/group.

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Row: Using the restriction type you can define row level access restriction. It uses the WHERE clause to restrict the data access.

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Table Mapping: Using the restrictions you can define alternate tables for particular group of user.

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I will be covering each restriction type in detail with example in others posts. Also you can play around with restriction types to understand its working.

Using Index Awareness in Business Objects Universe for Performance Optimization

What is Index Awareness?

Making universe index aware means telling universe on which columns indexes are created. This helps Business Objects to generate efficient query which uses indexes instead of actual column values which help to speed up the data retrieval.

e.g. If we have customer name in the query its useful to end user of report however we can use customer id to retrieve the data by making the use of index awareness which would help to fetch data faster.

You can define two types of index awareness in universe.

Primary Key: Using primary key index awareness universe can use index value instead of actual value of column. The query will thus use the key value. This helps database to fetch data faster.

Foreign Key: Using foreign key index awareness on object universe can filter the data without the need of join in query. Suppose you need to build a report which has filter on dimensions table. In absence of index awareness designer will use actual dimension values which requires join between fact table and dimension table. However if we had foreign key index awareness applied. Designer can apply filter directly in fact table using foreign key index. So this avoids join between dimension table and fact table. However foreign key index awareness requires dimension column values to be unique if same value is represented by different key. Then this may return unwanted result.

How it works?

Suppose you are building a report on Island Universe “Service wide Sale revenue.”, After you drag drop the object, You will see following query generated.

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Now if you see in the query, designer has joined Outlet_Lookup table to put restrictions on the states and using actual values from service table to filter the data.

Now Suppose we apply index awareness on service object defining primary keys and foreign keys.

The query will look as below.

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If you could see in the query, Dimension values have been replaced with actual foreign keys filtering data on fact table. Which is an efficient way to filter data? So query will run faster compared to earlier way.

However remember, index awareness might return wrong result if you have dimension value which have two different keys in dimension table.

e.g.

If we have data as below in service dimension

Service_id

Service

212

Activities

213

Activities

Now if you have index awareness applied on service object and using service as a filter in report. Since ‘Activities’ have two keys, Business Objects does not know this might put any of the PK as filter returning wrong data in report

While defining the index awareness for particular column you can also define the data restriction for the object using WHARE clause in index awareness. It’s very useful to restrict the data in index awareness.

e.g. for service object I can define service price WHERE clause as below.

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How to define index awareness.

To define index awareness

1. Right click on Objects to open its properties.

2. Open the Keys Tab

3. Define the primary keys and foreign key to be used in index awareness.

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Index awareness when used with proper data analysis can give you significant performance gains.

Recommended Book : SAP BusinessObjects BI 4.0 The Complete Reference 3/E


Linking Universe in Universe Designer

There are many times when universe development task is big and it’s not possible to dingle person to develop the universe in stipulated time. To cater this need Business Objects has provided the facility to divide the universe design task amongst several designers and then integrate the work in single universe using universe linking method.

What is Universe Linking?

Linked universe are universes which share common component such as objects, classes and joins. When two universes are linked the one universe is called as core universe. It’s the main universe which contains common components where other universe is called as derived universe. Changes made to core universe are automatically propagated to derived universe.

Uses and advantages of universe linking.

  • When you have to develop multiple universes but there are some common components across these universes in that you can create a core universe of common components and link it to other universes.
  • Linking of Universe enables to distribute the universe designing task amongst other developers.
  • It’s also helps to follow the code-reusability practices.
  • If there are any changes to common objects. It needs to be done only in core universe. It gets propagated to all derived universes.
  • Linking of universes help in universe maintenance.

Universe Linking Strategies.

Core Strategy: This strategy is used when you need to develop a universe for different functions. In such case you can create multiple universes for each function and the link all universes in single universe. This strategy allows us to create a common object only once and also help to split the universe design task amongst developers.

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Master Strategy: Suppose you have a requirement to create clone of existing universe. You can achieve this by creating another copy of existing universe however this will increase maintenance as you would need to maintain two universes now. To avoid that you can use master linking strategy. In which existing universe is linked to new blank universe so it creates a copy of existing universe with different CUID and we need to maintain only one universe as core universe is linked.

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Multiple Core Strategy: Now if you want divide the development task then you can follow this approach in which developers can develop their universe and at the link all universe in one universe.

Limitations and Restrictions of Linking Universes:

  • Both the universes (core and derived) must use same connection and should connect to same database.
  • Both the universe must be present in same repository in order to link.
  • Only one level of linking is allowed you can create derived universe from another derived universe.
  • Both universes should have unique object and classes. If there are duplicate objects/classes it will be renamed in core universe.
  • Tables from two universes must be joined after linking in order to avoid Cartesian product.
  • When core universe is linked in derived universe only classes, objects and tables are made available in derived universe. Context and LOV needs to be recreated in derived universe.

How to Link Universes?

To link universe make sure

  • · Core universe is exported to repository
  • · It’s open in designer.
  • · Now open universe parameters from File->Parameters
  • · Click on “Link” tab
  • · Click on “Add Link”
  • · Select the core universe to link.
  • · Click OK
  • · After this components from core universe will be available in derived universe and it will be grayed.
  • · Now analyze the derived universe and create joins between tables added from core universe.
  • · Create context/Alias wherever required.
  • · Save and Export the derived universe.

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Using Include to import one universe into another

In linking universe contents are not copied to derived universe and one cannot edit the core universe components in derived. However sometimes one need to merge two universe into one. For this purpose one can use “Include” universe approach instead of linking. When universe are included components of one universe are copied into another.

Difference between Linking and Including Universes

Including and Linking decision needs to be taken based on your own need following are the points which may help.

Linking.

  • · Core universe structure is created once and used in many derived universe.
  • · Only one copy of components from core universe exists in repository.
  • · Changes needs to done only to core universe and it gets propagated to all derived universe.
  • · Linking universe needs both the universe to be present in repository.
  • · Only one level of linking is allowed.
  • · Context and LOV needs to recreate in derived universe.
  • · Both the universe must use same connection and connect to same database

Including

  • · It’s the easiest and fastest way to copy universe into another.
  • · Context needs to redefine after including.
  • · Changes are not propagated from core to derived universe.
  • · Both the universe must exist in repository like in linking.
  • · One can easily maintain one universe rather than multiple universe o maintenance becomes bit easy.

Using Derived Table in SAP Business Objects Universe

What are Derived table and its use?

Derived table is not a physical in database however its logical table created in Business Objects Universe using SQL. Derived table can be considered like views in database where its structure is defined using SELECT statement.

Advantages of Derived Table:

  • Derived table in Universe lets you create a SQL statement to fetch data using various expressions, joins which is not possible using universe structure.
  • Its lets you put inline views (select statement in FROM clause) which are not possible in Universe normally.

e.g.

select agg1_id as id from

(select * from Agg_yr_qt_mt_mn_wk_rg_cy_sn_sr_qt_ma)

  • Derived table can be treated as normal tables and can be joined with actual table in Universe.
  • Its lets you merge data from different table which is not possible using normal in universe using underlying data sources.
  • One can embed prompts in derived table definition.
  • You can use derived table as a lookup when you have multiple fact table separated by contexts. Normally if you want to use measured from different fact table then Business Objects creates two queries one for each measure. Now some time this may result in performance issues. You can avoid this by creating a lookup table for different fact tables using derived tables.

e.g.

Suppose you have measure1 in fact1 and measure2 in fact2 and dimension is dim1. Now if you create a query with dim1, measure1, measure2 you will get two different queries. Now instead of this you can create separate derived table which includes dim1, measure1, measure2.

Disadvantages if derived table.

Since derived table is not an actual table you may face performance issues if underlying SQL query has performance issues.

How to Create Derived Tables

  • · From menu mar select Insert->Derived Tables
  • · Now write the SELECT statements which to define the structure of derived table. Remember to give Alias to column if you are using any expression in column list.
  • · Click on “Check Syntax” to confirm the definition of derived table
  • · Click OK

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· Join the newly created derived table to existing table.

  • · If you have context. Include the join in relevant context.
  • · Save the Universe.
  • · Now you can create object using derived table just like normal tables.

Nested Derived Tables

Nested derived table is nothing but a derived table using another derived in definition. It behaves similar to normal derived tables. Nested derived tables are generally using when underlying derived table is complex to build. In that case you can create different small derived tables and then use this derived table in main derived table.

Advantage of using nested derived table is the simplicity in derived table creating. Also Business Objects combines the definition in single SQL and it’s treated as single SQL.

Business Objects does not limit number of derived tables but nesting is limited to 20 levels.

You can create a nested derived table by using existing derived table in the from clause.

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