Dimensions and Measures, what are they?

Paul Scotchford
A free video tutorial from Paul Scotchford
Data Analyst and Qlik Development Specialist @ awari
4.6 instructor rating • 5 courses • 105,820 students

Lecture description

A brief discussion about Dimensions and Measures as we use these throughout the course.

Learn more from the full course

Certificate in Qlik Sense Analytics Development

Real world data scenarios for Qlik Sense app development

13:52:11 of on-demand video • Updated November 2021

  • Business Intelligence & Analytics development
  • Skills needed to become a data analytics & visualisation engineer
  • Identify KPI's,metrics and dimensions from your business requirements
  • Design and build data visualisations using key Qlik Sense features
  • Understand the associative data model and how to load data to it
  • Resolve data integrity and modelling issues like synth keys and circular references
  • Code expressions for metrics and dimensions, we learn set analysis coding too
  • Explore downloadable source code & data during your development work here
English dimensions and measures what are they well basically we have to understand these because they form the fabric to our underlying data structures within our Qlik Sense apps so let's look at the dimension first of all by definition the dimension is a structure that categorizes or describes facts and measures we'll discuss facts and measures a little later into the lecture so for example a date is a dimension as it categorizes a measurement in other words a fact into a temporal representation so for example the date a sale of a product took place the product that was sold is also a dimension as it describes what was sold now the dimension can be organized into a hierarchy as required now the calendar is an example of a hierarchy so in this basic example we can see that we have a date which is our finest grain in other words the lowest point in the hierarchy and we can group dates into months and we can group months into years and of course the scope for this grouping is quite vast it really gets to a use case scenario for your application now another example would be that products can also be grouped into categories and subcategories in a Qlik Sense data model we would have dimension tables to store these values such as what you see on the screen now that's a calendar dimension within one of the models we're going to develop within this course so when we're referring to the measure by definition a measure is a property on which calculations can be made for example some average count and so forth hence for example when a product is sold it's recorded in a table and this table is known as a fact table hence the sale is recorded with properties also known as dimension columns that a calculation can be made so the sale amount is one such property that can be aggregated via a sum to establish the total sales for a product and a Qlik Sense data model we would have fact tables to store these events as you can see on the screen now there's our 2015 sales and we can see an association to the products that were recording the sales against so let's look at a sampled Qlik Sense app to get a feel for dimensions and measures we'll use the executive dashboard app and you can also download this from the Qlik Sense demos website and the url is in this lecture resources list for you to link to ok we have the executive dashboard sample app on the Qlik Sense desktop hub by way of my local host url now i got this particular app from the Qlik Sense demos website which is included in this lecture resources and you can download any of the apps that have this tag downloadable now of course you'll need to create a login if you don't already have one so just when you try to log in at the bottom of the page you'll see a sign up option then you can sign up to get these downloads now there's no cost here this is totally free it's just a click thing to sign up with everything and get those free resources now let's get back to our app i'm going to open this app up and firstly i'm just going to demonstrate the underlying model so we can see what the dimensions and facts are all about so if we go to our data model viewer we can see we have a model now don't be intimidated by this model at this point because we're going to get more into modelling as we move forward with our development process but for now what we can see are a fact table and you'll notice all of the others that lit up with the orange highlight are saying they have a direct association to the fact table so what are these other things that lit up well they're actually dimensions as you can see so you remember we talked about a basic calendar well here's a calendar dimension and it associates by way of this column called well it's a date format i probably wouldn't name it that way but that's the way it is in this sample app and all of the other tables we see that surround the fact table are in fact dimensions but some of them don't have direct associations that kind of inferred through for example the item branch master goes to the item master and it has other associations along with it now we'll cover this in our data modeling lectures later on but for now all we need to understand is that we have a fact table here and a number of dimensions that help describe or categorize the events that have been recorded in our fact table and a cool feature with the data model viewer is we can actually preview our data you'll notice on the left hand side if i show preview and select a table such as the fact table we can see all of the columns within the table itself and the values so let's look at our calendar and there's our calendar data and we also get an indication of how many rows there are in that particular table now by definition everything is a table it's just that they're classed differently dimension tables and fact tables let's go back to our application hub and create a new sheet and visualize a dimension and a measure if we go to app overview we can see all of the sheets that are created within the app so the app itself is a container in its own right it is made up of one or more sheets for the user to consume information about and derive inside of course so let's create a new sheet and yes you can create new sheets within these downloadable apps what i do here nothing fancy let's edit the sheet after i've created it and what i'll do is go to the charts option i don't worry too much about the detail here because we're going to learn all about this moving forward and because it's a straight table in other words a simple table i'm going to add a column aka a dimension and what i'm interested in is the product group all i have to do is select that now i don't need to add anything else here i have a list of the product groups that are within the data model behind the scenes and that's actually coming from that product group master dimension table let's say we want to dissect aggregations about all of these dimensions well what we can do here is add for example a pie chart so let's drag it onto our sheet here and we need to add a slice and an angle and in this case we can take that from the product group so let's add our dimension product group and the measure in this case what we'll do is understand the individual sales shares for those product groups so what i have to do here is look for the sales amount we'll select that and Qlik Sense kindly offers you an aggregation option we have sum count average min max of course there's lots more but they're the fundamental basics for any of the aggregations we might do in some of our charts so let's select that and instantly we can see the individual shares based upon the individual product groups so we can see we have produce which is around 20 of our sales it seems to be the largest overall we can see the product group produce on the left hand side here if i select this what will happen everything filters based upon my selection on the screen here so we can see product group produce we have a sum of the sales amount and because we're only displaying one dimension it's a 100 percent share now to remove that filter all i have to do is click the x here i'm just going to save this so we don't lose it and we can just scroll these values around as well by using the scroll wheel as long as you're hovering over the object you can see here we're scrolling it through let's edit the sheet perhaps we'll change the appearance we might actually change this to a donut style and i might influence the coloring as well by going to colors in legend and what we'll do is remove the legend title and instead of having auto colors i'm going to select the colors by measure and what you see now the color intensity is set based upon the underlying value as you can see produce is the highest percentage so it has the darkest color okay we're going to cover this in more detail obviously but what we're seeing here now is a demonstration of dimensions which we use for selections and the calculation across those dimensions you can also filter simply by selecting the segments within the pie chart let's select deli click confirm selection and there's our daily value okay so that's a good starter or a primer if you will on dimensions and measures let's look at creating our first app in the next lecture see you there soon