DEV Community: Mwakaa D

Introduction To Power BI

Mwakaa D — Sun, 29 Mar 2026 05:59:45 +0000

Power BI is a special tool used in management of data via simple ways of manipulating data. Some ways to manipulate data is by use of relationships,joins and schemas. The above are going to be discussed below. Keeping in mind that power BI is not such a hard concept to understand but one has to give it a considerable amount of time and effort so as to ensure a smooth ease into the mind.

TYPES OF RELATIONSHIPS IN POWER BI

Power BI supports multiple relationship types between tables, including one-to-one, one-to-many, and many-to-many, with options for single or both-directional filtering.

One to One

This is where a single row in a table corresponds or rather relates to another singular row in a different table. The two row have to have different values so as to reinforce the 1:1 relationship.

One to Many

This is where a single row in a table corresponds to multiple other rows in another table. For example in a supermarket, assuming that there is a customer row, it may relate to other rows showing the products purchased.

Many to Many

This is where multiple rows in a table corresponds to multiple other rows in a different table. This can be done by creating multiple many to many relationships.

Filtering

Single direction

It filters contexts from the one table to the many table. IT is usually the most recommended one.

Both Direction

It is also called Bi-direction. It filters contexts in both directions as the name suggests. This means that when a change is made in one table it reflects in the other table.

Power BI allows multiple relationships between the same tables, but only one active relationship can be used by default in visuals. Inactive relationships can be activated in DAX calculations.

Types of Schemas in power BI

Star Schema

It is called star because the fact table is usually at the centre with the dimension tables radiating outwards therefore resembling a star. A single fact table only contains quantitative data such as sales. A multiple dimension tables contains descriptive data such as product categories.
Advantages
It simplifies queries and improves performance as most relationships are one to many.
Easy to understand
Optimized for DAX calculations.
It is used sales reporting, inventory management and wherever clear metrics are tied to multiple descriptive attributes.

Snowflake Schema

Dimensions are normalized into multiple related tables, therefore one can say its a variation of the star schema

Advantages
Can be used for complex data
Saves storage space

Disadvantages
Harder to Navigate
If not modelled carefully, complex queries can reduce performance.

Galaxy Schema

Its where multiple fact table are connected as they may share common dimension. Its suitable where businesses have multiple areas of analysis like sales and inventory which share dimensions such as date and products.

Advantages
Flexible for larger enterprises
Enables combining different areas of business metrics in the same model

Disadvantages
Can be challenging to optimize DAX measures

Types of Joins in power BI

Joins are used to merge two tables

Left outer

All rows from the left table and matching rows from the right side table are joined. If they do not match, nulls are returned for the second/right table.

Right outer

Works the same as the left outer but with a little difference. So rows from the right table and matching rows from the left/first table are joined. But this time if there are no matches, nulls are returned to the first/left table as opposed to the left outer join where the nulls are returned to the right/second table.

Full Outer

All rows from the tables are joined with nulls returned for missing values.

inner

Only rows that match from both tables are merged.

Left anti

Rows in the first/left table that do not have a match with any rows in the right/second table.

Right anti

Rows in the second table that do not have a match with any rows in the first/left table.

In conclusion, Power BI is a rather simple tool used in data management but if one does not give it the time and put in the amount of work, it may turn out hard for them to understand it fully. Most of functions, queries, DAX calculations... are to some extent interconnected therefore making them easier to relate to one another.

Intoduction to MS Excel for Data Analytics

Mwakaa D — Mon, 26 Jan 2026 11:40:57 +0000

Excel is a some what simple tool that is available for most if not all windows but its version varies according to the version of windows being used.
Some of the uses of MS Excel are data organisation and storage and its useful in even clear calculations which is performed using formulas.
When you enter excel in your device, you are presented with a workbook. You can use as many workbooks as you feel obligated to which will be saved to your workbook
Columns in your work sheet are labelled in letters while rows are labelled in numbers

Inputing data

As i stated in the beginning excel can be used to store data. This data is usually simple to input as no formulas or commands are required but rather just a simple input of the exact data you want to work on.You can input data such as names, numbers etc
Lets say you are a clerk in a school, you can input students names, school identification card numbers, even their class...etc
Its not really a must for this to be said but your data has to be presantable so that in future when you need to find a student, it will be easy.

Formulas

Formulas are the kinda commands that are used with numerical values to work on them same as formulas in mathematics. These include sum, average, count, Max, Min...etc. There are many formulas with different uses.
When you select a cell where a formula was used, the formula is displayed at the formula bar above your data

Sum

This formula is used to sum up all the numerical values selected as the name suggests

Average

The formula is used to find the mean of the data selected

Count

It is used to find the number of numbers selected. What i mean is to find how many numbers have been selected to be worked on

Max

Finds out the highest value of the data selected

Min

Finds out the lowest value of the data selected

Sorting and Filtering

Sorting is arranging data in a specific way so that it is more pleasing to the eye and easier to work with
To sort your data, select your data by clicking control + A then go to your home button and click sort to sort your data in a certain way. For numerical data you can arrange it from largest to smallest or smallest to largest while for text-like data you can sort it from A-Z or Z-A.

Filtering is basically working on only a small part of your data at a time of your own preference. This improves efficiency because by working on only a small part especially if you have a large dataset, you get to see exactly what you are working on at the time.

Chart Analytics

Charting is basically displaying your data in form a chart. Charts are more pleasing to the eye than large text-form data therefore inorder to truly view your numerical data clearly, charting is highly advised. There are many types of charts and you can use them according to your preference. They include bar, line...and many more. For a large amount of data, You can use a combo chart which combines different types of charts and different types of data.
Charts are found at the insert part of your workbook

Conclusion

Using MS Excel is not necessarily a hard thing to do but the most advisable is to take it one step at a time so that you can practice any simple thing you do before you move on to the next. This will enhance remembrance rather than rushing through the learning process then later you remember very little.

Understanding The Markdown Language

Mwakaa D — Fri, 16 Jan 2026 06:33:49 +0000

Understanding Git and Github

Pushing and Pulling code

Pushing code basically well how i understand it is, just as the name suggests. For example what happens when u push a pen into my hand, u just handed me a pen right, well pushing code is basically the same thing, adding a line of code to Git and the changes are observed in the repository in your Github. For this to be done, one must have made a repository in Github where there is a button in the Github home screen, one can add a name to the repository and alter its visibility to the public by either making it private or public. Lets name mine Project. Now the problem most people face is adding code to the git which will be applied to the github repository. So first one must make a typically a subfolder but in coding or rather in git its called a branch. So per say i named mine origin, so we have to first change our directory to the branch so that we can be working on it directly. We have to make a directory or a branch directly on git by using the command mkdir (origin). That command basically makes a directory. Then we are supposed to open the directory which is connected to the repository so that we can make changes to it by using the command cd (origin). That code line changes the directory to origin from the main branch. We can then add kind of subfolders in the branch origin. To do this we use the command line touch, then the name of the subfolder. so lets say you want to make a subfolder called Kenya, you will input in your Git the line touch Kenya. Then to top it off we will add the line git add ., so as to add the changes to the repository. So in the main repository called Project, we will have a branch called origin with a smaller branch called Kenya.

Tracking Changes

It doesnt have to go by saying that whatever you input to your repository has to be to your liking. Therefore one must be able to track the changes that they input to their repository. To do this, you have to type the command git config --list
That line of code makes it that the changes that you had made while pushing your codes ca be viewed all in one place so that you know if you hade input the right codes

Version Control

This is typically being able to know if the version of git in your device is compatible with your machine so as to ensure its use to its full capacity. Doing this makes it that your projects are easier in both doing them and even saving them to your repository. To do this one has to put in the command git --version

Conclusion

As observed by the short examples i was able to give, the markdown language is easily understandable and if put into practice, hardly unforgettable.

Last but not least

This is just a short introduction that i should have done at the beginning

My coding experience as far as the year has proceeded has been very smooth even as i learned Markdown, Python and even other languages. All these I have been able to do through the support of the staff of The Lux Dev Community. They have been very supportive in my endearvors as i proceed together with them.
Lux Dev is a school located at Garden estate, Kanyagia drive.I learned about them through a friend who recommended me to them because as he said, He likes the way they teach as they make coding easier. Of course i had to check this out for myself so i did a little bit of research and found out that even though it was founded in 2019, it has a vast allumni where you find that most of them are doing pretty well in the real world. I dont know its just the effect that comes with being one of their allumni but i was intrigued so i enrolled in their Data science and Analytics course. They also offer Data Engineering. One thing that makes me happy to be a part of the school is the support they offer when your stay with them is not smooth for you. It really motivates one to work hard during their stay there.
My hopes are that i really benefit from this not just coding-wise but even in the interactions that happen on a day to day.