Introduction to QlikView ApplyMap
We all are aware of the MS Excel function Vlookup which performs the mapping table task. In the same way, to simplify the composite data model, we need to map the table, so here we do this by using the Applymap() function. This QlikView Applymap() function helps to deliver a substitute method of carrying out joins between the table columns of two, unlike tables based on a key column that is mutual to both tables. Thus, this lessens the number of tables contained in the data model. In Database, Data mapping can be defined as a procedure of forming data components from two distinct data models, which are done for the perseverance of data transformation generous of data integration jobs.
- In QlikView mapping, a mapping table is always created by Mapping Select or Mapping Load before applying a Map function.
- Until the script program is executed entirely, the mapping table will temporarily reside in QlikView’s memory. After the script execution, it will be released.
- The core data tables will not be affected by the temporary mapping table, which is stored in the QlikView’s memory.
- As often as per the user’s need, any mapping table can be reused and recalled in a script.
- The primary field in a mapping table is always denoted as a key, and the following one field or a column is denoted as mapped values.
- In one script all the mapping necessities can be applied.
QlikView ApplyMap Function
The QlikView Applymap() Function can be defined as a lookup function implemented for mapping the table column to the specific table through the mapping columns of the table. We can view the syntax of this function as follows:
Applymap function(‘Name of Mapping Table’, Mutual Key Column, ‘The Default Value’);
Let us see the parameters used in the Applymap function shown above:
- Name of the Mapping Table: The function’s initial parameter states the name provided to the mapping table. It conveys QlikView, to which mapping table one must use the lookup function. Here, the name of the table must be written beneath single quotes.
- Mutual Key Column: The second parameter is the common key column. It signifies the primary column of the mapping table that is nothing but just a key column or a lookup column.
- The Default Value: It is the last third parameter in the syntax which describes the default value that is an optional one. It is applied to control the null values when there is no match between the two tables’ mutual/common key columns.
Suppose the user needs to map countries and their best performers in external sales in each place of an association. It can be executed within no time using the QlikView mapping function.
QlikView ApplyMap Mapping Load
The Mapping Load statement in QlikView is implemented to load table fields and values into a newly formed mapping table.
Here, the term Mapping is applied as a prefix to SELECT or LOAD statements imposing the system for saving the loaded fields performing the mapping table. Normally, this mapping table consists of two columns; the initial column includes values for comparison, which may be a reference point, and the next includes the desired or resultant values based on the comparison.
Suppose we have declared that numerous tables present in the data model may be bad, so the user may not want to have a condition where the user might have several lookups joined to the statistic table. Thus, we can decide this by making the mapping table and converting out the related ID with the value through ApplyMap. In its modest form, one can even build a mapping table providing a specific name, which is further implemented in the Applymap statement, that switches the ID specified for the value.
For illustration, the user can have the country codes as the reference column and the following country names as the second resultant column. When we execute the script, the country codes are substituted by the corresponding country names.
Let us see the instance in QlikView of mapping load as follows:
//Loading country codes mapping table MapCountry: Mapping LOAD* Inline[ CountryCode, Country Ind, India Ity, Italy Dk, Denmark Sw, Sweden ];
On execution, the above code will load the MapCountry mapping table consisting of two tables: CountryCode and Country. The statements and functions like Applymap can further use the contents of these mapping tables.
QlikView ApplyMap Statement
- The Mapping Load or the Mapping tables are a substitute for the JOIN statement executed in the database. Here, mapping to the load statement states QlikView that a table is Mapped with another. This mapping table consists of two table columns: the first is the lookup value, and the second one is the mapping value. The Mapping tables are temporary since they are detached spontaneously from the data model through the end of completing the script.
- The Mapping Load statement is operated to the stack fields plus values into a newly created mapping table in QlikView.
- We can create various maps from a similar table.
- This mapping function saves processor memory as well as time.
- It also helps to clean up the information data by removing the info disparities.
- The Mapping table prevails there only during load.
- Normally, the QlikView Applymap statement aids in developing the light task of setting complications in the data model, which can lead to severe performance concerns.
Given below are the FAQs mentioned:
Q1. What is apply map and mapping load?
The Applymap() function is implemented to map the Mapped table in the database to the next table, whereas the Mapping Load statement is applied to load the mapping table.
Q2. How can we differentiate between join and applymap functions in QLikView?
The Join is used for selecting a set of results of the source tables and operates on multiple fields plus their values having four categories: inner, outer, right,, and left. However, when required, the Applymap is a reference lookup kind, and it takes only two table fields for mapping.
Q3. Applymap function in QlikView not working when used with dates such as TIMESTAMP?
The date is a format type function that stores numeric data having times, whereas QlikView looks up the numeric value with no matches since other entries are thereafter decimal point in the mapping table. You can use the function Date(DayStart(…)), which removes the time part, as a solution in place of Date().
This QlikView ApplyMap() function is related to the lookup function in the Excel sheet, where the table’s field value is implemented as a reference to another field present in the mapping table, which outputs a corresponding result. Also, it assists the user in cleaning up or repairing the differences found in the source data by transforming the field values as necessary.
This is a guide to QlikView ApplyMap. Here we discuss the introduction, QlikView ApplyMap function & mapping load, statement, and FAQ. You can also go through our other related articles to learn more –