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Jan 24 β€’ 10 tweets β€’ 3 min read β€’ Read on X
One concept I struggled to understand as a Data Analyst was DataBase Normalization

I'm going to explain it to you so you don't have to

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What is DB Normalization?

Database normalization is a process that aims to organize data efficiently while maintaining data integrity and flexibility.

It is achieved through a series of progressive stages, known as Normal Forms (NF), each building upon the previous one.

Let's delve into the different levels:
1. First Normal Form (1NF):

At this initial level, a table is considered to be in 1NF if it has no repeating groups, and all the entries in each column are atomic (indivisible).

This ensures that each piece of data is stored in its most granular form.Image
2. Second Normal Form (2NF):

A table reaches 2NF when it meets 1NF criteria, and all non-key attributes are fully functionally dependent on the entire primary key.

This eliminates partial dependencies and enhances data consistency.Image
3. Third Normal Form (3NF):

In 3NF, the table is further refined by removing transitive dependencies.

This means that non-key attributes should not depend on other non-key attributes.

Achieving 3NF minimizes data redundancy and increases data integrity.Image
4. Boyce-Codd Normal Form (BCNF):

BCNF takes 3NF a step further by addressing issues related to superkeys and candidate keys.

In BCNF, for any non-trivial functional dependency, the left-hand side must be a superkey.
5. Fourth Normal Form (4NF):

4NF deals with multi-valued dependencies, which occur when one or more attributes have multiple values for a single combination of values in other attributes.

Achieving 4NF ensures further elimination of data anomalies.
5. Fifth Normal Form (5NF) or Project-Join Normal Form (PJNF):

The highest level of normalization, 5NF, addresses cases where a table contains join dependencies.

This level is less common and is primarily applied in complex database scenarios.
It's important to note that not every database needs to achieve the highest level of normalization.

The choice of the appropriate level depends on the specific requirements and use cases of the database.

Striking the right balance between normalization and performance is a critical aspect of effective database design.
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More from @freest_man

Jan 25
If you are Aspiring to be a Data Analyst it's key to know the steps of a Data Analytics Project

8 Key Steps of a Data Analytics Project:
Developing an analytics solution begins with requirements gathering.

From there the process continues to ingesting, processing, and exploring data.

Analysis and solution deployment are followed by requesting feedback from the business.

Finally, the analytics solution is optimized and the process begins again.Image
1/ Requirements gathering

Data teams work with the business to understand business needs and the intended outcomes of an analytics project.

Here are some questions which are asked to understand business needs:Image
Read 11 tweets
Jan 21
Data Analytics can be divided based on the 5 types of questions it can answer

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Descriptive analytics

What happened?

Descriptive analyticsΒ answers questions about what happened.

Descriptive analytics techniques summarize large datasets to present insights to stakeholders.

The presentation of data related to those KPIs is descriptive analytics.Image
Diagnostic analytics

Why did it happen?

Diagnostic analyticsΒ helps answer questions about why things happened and is the next step in data analytics after descriptive analytics.

Analysts take findings from descriptive analytics and dig deeper to find the cause.

Diagnostic analytics generally occurs in three steps:

Identify anomalies in the data.
Collect data that are related to these anomalies.
Use statistical techniques to discover relationships and trends that explain these anomalies.Image
Read 7 tweets
Jan 20
Every Dashboard is intended for a certain Audience

Let's look at 3 types of Dashboards based on the Audience

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There are three types of dashboards based on your audience

1. Operational dashboards - Intended for Managers

2. Strategic dashboards - For Executives

3. Analytical Dashboard - For Analysts Image
1/ Operational Dashboard

This kind of dashboard monitors the day-to-day metrics

It answers the question β€œWhat is happening now?”

Managers oversee the operations so they can use the data for decision-making

This dashboard oversees the daily transactions of the business Image
Read 7 tweets
Jan 16
STAR methodology is compelling in Interviews and often comes in Clutch

Ensuring a structured presentation reinforcing the gravity of their candidacy.

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Imagine chatting about your experiences in the interview using a straightforward formula without stumbling on your words– cool, right?

STAR helps you gain the ability to articulate experiences with precision and explain both challenges and accomplishments
S -> Situation

The interviewer may ask you about a specific project or problem you've worked on.

Start by providing a clear and concise overview of the situation.

Explain the context, the project's objectives, the data available, and any challenges you faced.

This sets the stage for the interviewer to understand the scope of your work.
Read 8 tweets
Jan 6
🧩 SQL Joins Explained with Query + Visual

Joins in SQL is a fundamental concept to combine data from different tables based on related columns.

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1/ INNER JOIN

This type of join returns only the matching rows from both tables.

It's like finding the intersection of two sets.

Perfect for retrieving data that share common values in specified columns! Image
2/ LEFT JOIN

Returns all rows from the left table and the matching rows from the right table.

Useful when you want all the data from the left table, regardless of whether there's a match in the right table. Image
Read 9 tweets
Jan 3
Turning your ML models into Simple Streamlit apps can land you a Data Science job

Let's create Your First Streamlit App

Step by Step Code Explanation with Code

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Streamlit is a Python library designed to help you turn data scripts into shareable web applications effortlessly.

Imagine transforming your data visualizations and analysis into interactive apps with just a few lines of code.

Here's an introduction guide to Streamlit:
This Streamlit app is a simple yet powerful tool to visualize historical data for selected stocks.

Let's break down the code step by step:
Read 10 tweets

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