One of the most common things I do during taking interviews is to give real life scenarios and assess the person on how he tackles the situation. Most of the times, what I really look for is how he goes forward in solving the problem – the approach and the way of thinking rather than the answer itself. Another thing that I look for is whether he tries to put some extra effort to implement the solution (especially the reporting part) in an aesthetic and user-friendly way. Most of the candidates would know the answer to some simple question like how to add data labels to their charts but they stutter when I ask what are smart labels or how can we prevent the cluttering of data labels. I would easily give brownie points to someone who details his solution with some extra attention to details. It must be my frequent rendezvous with creating big reports that make me extra fond of document maps in SSRS and an essential part of my SSRS interview questions.
It is hard to imagine going through a big book that has no table of contents. But many users and developers have no problem at all in designing big reports without any navigational aid (although at some point of their wretched life, the users are going to curse the person who developed those reports), even though Microsoft has provided this feature. Document Map is a navigational feature in SSRS that, when implemented, allows the user to navigate through the document and its hierarchies. With this feature, you can add a panel to the left of the reports where you can have the list of “contents” of the report. What makes it more special is that on clicking the “content” in the list, you will be directly taken to the page where the content is present. Cool feature, huh?
Requirement
Suppose you already have a matrix or a table with some groupings as shown below
Suppose the number of subcategories are very large and spans into multiple pages and the requirement is such that each user has to specifically search for a set of subcategories at a particular time of the day. It would make his life a lot easier if there was a document map listing the subcategories on clicking which he would be directly taken to the clicked subcategory
Solution
1) Go to the design mode of the report and click on the group properties of subcategory.
2) Go to the advanced tab of the properties and set the Document map as the field Subcategory (you can select the appropriate field name from the drop-down).
3) Save the report, deploy it and then preview it .
Already you can see the panel at the left hand side which contains the list of subcategories. To hide/unhide this panel, you can click on the icon that has been highlighted in red in the above image. Notice that the “Document Map” text highlighted in blue is the report name.
4) Now you can click on any of the subcategories, say Handlebars and you would be taken to the page where the clicked subcategory is.
5) (a) You can also make document map labels for each of your report item. For eg, if you have 2 tables, you can click on the table and press F4 to see the properties.
5) (b) You can give the required name in the DocumentMapLabel property as shown above and then see the required result when you preview the report.
6) Now that you have seen the toggle symbol, you would have already guessed that it is possible to create hierarchies also in the document map label, for e.g., Subcategory—>Product. For that, all you need to do is to enable Document Map property for the Product group also.
Note
“ Document Map is mostly for
HTML rendering. Other renderers render differently.o PDF: Uses Bookmarks.
o Excel: Uses named worksheet with hierarchical links. Report sections appear in other sheets.
o Word document also has a document map like the table of contents.
o Tiff, CSV, and XML ignore this setting.
o Recursive data is related to the idea of self joins where the relationship between parent and child is represented by fields in the dataset. “
So there ends the part 3 of my interview series. In my next blog, I would be taking a momentary break from my interview question series and presenting a very interesting application of Document Maps, wait for it :)
Important
Understanding Tablix Visual Cues 
The Row Groups pane shows the parent group Category and child group Subcat. The Column groups pane shows the parent group Geography and child group CountryRegion, and also the Year group, which is an adjacent group to the Geography group. When you select the Subcat group in the Row Groups pane, the group bar turns a darker shade of orange, and the corresponding row group member cell is selected on the design surface.
For a Tablix data region that displays detail data, the details group is the innermost child group. Rows that you add to a details group repeat once per row in the result set for the query for the dataset linked to this Tablix data region. The following figure shows the last page of the rendered report. In this figure, you can see the last detail rows and the subtotal row for the last order.
For each column in a Tablix data region, the same principles apply. For example, a column is either inside or outside each column group; to display totals, add a column outside the group. 
Note
The dotted lines show the four tablix areas. The row group area has a row group header that controls the category labels in the first column. Similarly, the column group area has a column group header that controls the geography labels in the first row. In preview, as the matrix expands across the page, the first row displays the column headings, as shown in the following figure:
To repeat or freeze column headings in the first row, set properties for column headers on the tablix data region. Column headers for nested column groups are automatically included. 
There are no dotted lines because the table consists only of the tablix body area. The first row displays column headers, and represents a static tablix member that is not associated with a group. The second row displays detail data, and represents a dynamic tablix member that is associated with the details group. The following figure shows the table in preview:
To repeat or freeze column headings, set properties on the tablix member for static row that is part of the tablix data region definition. To select the static row, you must use the Advanced mode of the Grouping pane. The following figure shows the Row Groups pane:
In Advanced mode, the following figure shows the static and dynamic tablix members for the row groups in the table:
To repeat or freeze column headings for the tablix member, select the static row that is labeled (
The dotted lines show the tablix row groups area and the tablix body area. The row group area has a row group header but no column group header. The following figure shows this table in preview:
To repeat or freeze column headings, use the same approach as the previous example. The following figure shows the default view of the Row Groups pane:
Use the 
For tablix members are listed: 
The table has three rows. The first row contains column headers. The second row contains the group value and subtotals. The third row contains the detail data. There are no dotted lines because there is only a tablix body area. The following figure shows this table in preview:
To control how the rows repeat or stay in view, you must set properties on the tablix member for each row. In default mode, there is no difference between this example and the previous example for a table with a row group and a group header. The following figure shows the Grouping pane in default mode for this table:
In the Row Groups pane, the following tablix members are listed: (