Connecting to Data Sources
You can connect to database from the front page of Tableau by clicking on either of the following.
- To a file
- To a server
- Save Data Source
Data Types
There are 8 data types of Tableau.
Dimension and Measures
When you connect to a data source, Tableau automatically assigns each field in the data source as a dimension or a measure. You can find these in the data pane which is split into two sections (DM): dimensions at the top, and measures at the bottom. A faint grey line separates D’s from M’s.
Dimension (Blue)
- Dimensions contain qualitative values (such as names, dates, or geographical data).
- Dimensions are used to categorise, segment, and reveal the details in data.
- Dimensions affect the level of detail in the view.
- Dimensions are descriptive field in the data set which represents few distinct values. Examples − Month, Year, Product ID etc.
- Note that Dimension being a qualitative in nature, and it can equally be a number.
Measures (Green)
- Measures contain numeric, quantitative values that can be measure.
- Measures can be aggregated. For example, they are summed, averaged, or counted, or the result is the minimum or maximum value.
- When you drag a measure into the view, Tableau applies an aggregation to that measure (by default)
- Measure is a numeric field on which some calculations are performed for each distinct value of dimension. (It is quantitative in nature, and calculation is usually performed with it).
Discrete Fields and Continuous Fields
Discrete (Blue)
- It is usually in blue colour.
- It defines labels.
- The order of discrete can be re-arrange and it will still make sense.
- It has a value which can be represented either by row or column.
- Discrete (blue) fields have values that are shown as distinct and separate from one another.
Continuous Fields (GREEN)
- It is usually green in colour.
- It defines axis.
- It is illogical trying to change the order of arrangement of continuous fields.
- It is has a value which can be represented either by row or column.
Discrete Date Parts and Continuous Date Values
- Date under the discrete parts are separate within the histogram and not in the case of the continuous date types.
The upper part is the discrete date value and the Lowe part is the continuous date vale.
Ratio Calculations
- There might be a need to calculate the value that are not included in our data, and the Tableau function allows us to calculate ratios or some other functions within our data. Example, we might be interested in calculating the profit ratio from our data sources that contains sales and profit data. In this case, we will create a calculated field for profit ratio using data from the sales and profit fields.
- Step 1: create a calculated field
- In a worksheet in Tableau, select Analysis > Create Calculated Field.
- In the Calculation Editor that opens, give the calculated field a name. In this example, the calculated field is called Profit Ratio.
- Step 2: Enter the formula
- The new calculated ratio will appear in the measures panel, and this can be drag to the display window for analysis of our data.
Manage Data Properties
- This involves the renaming the name of the table column and the data types. We can change the data names direct on the table, and this changes will not affect the main database that was uploaded in the Tableau but rather, it will only be limited to the catches that we are working on.
- We can equally right click on the dimension/Measures list to change the name of the data set.
- Alias: We can equally create an alias to generate name an alternate name for data set. Aliases can be created for the members of discrete dimensions only. They cannot be created for continuous dimensions, dates, or measures.
- Assign Geographic Roles: we can change the assignment of a variable to a geographic field.
- Changing the data types: We can change the data types to our suitable data types.
- We can enable data label by clicking the “T” icon on the menu
- To change the data to a currency format, right click the data types in the data, and select >default properties >select >number format
- You can do a lot of format under the default properties and there are different list for data that are dimension and measures