It’s the second month as a data science mentee and all I’ve experienced is massive growth and productivity, although the challenge bar was raised and more sleepless nights as we were introduced to some data science visualization tools, like the power BI and Tableau Public and the most commonly used tool for data analysts and scientists, SQL (Structured Query Language).
A brief summary of the resources
week 1 - SQL (Structured Query Language)
It is the most commonly used data analysis tools for data analysts and data-scientist, a programming language used for communicating with and extracting data from databases.
To view data in a database an ERD (Entity Relationship Diagram) is used to visualize how data is connected with the aid of a data flow diagram showing the names of the tables , columns in each table and the way the tables work together.
Types of SQL databases
- My SQL
- Access
- Oracle
- Microsoft SQL server
- Postgres
In this article we will focus more on My SQL database.
MySQL Database
This is a relational database management system based on SQL — Structured Query Language. The application is used for a wide range of purposes, it can be used to store anything from a single record of information to an entire inventory of available products for an online store. The most common use for MySQL is for the purpose of a web database.
The key to SQL is to understand the statements i.e a piece of correctly written SQL code. We have 3 types of Statements
- Create table i.e creates a new table in a database
- Drop table i.e Remove a table.
- Select i.e Reading a data and displaying it. It is the most common statement used by analysts ,mandatory and must be included in every query.
Types of My SQL Operators.
1. Arithmetic operators
They are used to derive new column known as derived column in SQL . They are:
- Multiplication
- Addition
- Subtraction
- Division
2. Logical operators
- LIKE : This compares a value to similar values.
- IN : This compares a value to a list of literal values that have been specified.NOT : This reverses the meaning of the logical operator with which it is used.
- AND : This compares a value to any applicable value in the list as per the condition.
- BETWEEN : To search for values that are within a set of values, given the minimum value and the maximum value
- OR : This combines multiple conditions in an SQL statement’s WHERE clause.
- IS NULL : This compares a value with a NULL value.
- ALL : This compares a value to all values in another value set.
SQL keys
It is either a single column or a group of columns that can uniquely identify rows in a table. Although there are seven keys , two keys were focused on during the lesson.
- Primary key : It is a unique column in a particular table and we can’t have more than one. It is the first column in each tables.
- Foreign key : It is a column in one table that is a primary key in a different table. We can have more than one foreign key in a table.
Week 2 -Tableau
Tableau is a data visualization software used in datascience. A workbook contains sheet. A sheet can be a worksheet, dashboard or a story.
- Worksheet : It contains a single view along with shelves, cards, legends, and the Data and Analytics panes in its side bar. see The Tableau Workspace for more insight.
- Dashboard : It is a combination of several worksheets that you can arrange for presentation or to monitor. The Dashboard and Layout panes are available in its side bar. See Dashboards for more insight.
- A story contains a sequence of worksheets or dashboards that work together to convey information. The Story and Layout panes are available in its side bar. See Stories for more insight.
Types of Data in Tableau
- Dimensions: The fields in this section cannot be aggregated.
- Categorical
- Quantitative
- Time data
2. Measures: The fields can be measured, aggregated or used for mathematical operations.
To combine data from multiple sheets to a table, drag multiple sheet into the top panel using either joins or unions.
- A UNION concatenates result sets from two queries. But does not create individual rows from columns gathered from two tables.
- A JOIN compares columns from two tables, to create result rows composed of columns from two tables.
To learn more on tableau public you check out youtube, google or look out for fee courses on udacity ,data campe etc.
Week 3 -Power BI.
Power BI is the leading visualization tools. It supports the collection of software services, apps and connectors that works together to turn unrelated sources of data into insights through easy to use customizable visualizations.Check out this article I wrote on power BI for more details
Week 4 -Technical Writings on summary of Power BI ,SQL and Tableau Public.
I had fun learning the SQL language and In my opininon it’s quite a simpler language compared to python but maybe not as a tool.
Accountability is the glue that ties commitment to results.
- Bob Proctor
For someone whose shortcut to achieving goals entails being accountable, this SCA program has been really helpful in that expect. It provided me with the accountability I sought after by placing me in the care of a selfless and empathetic mentor who is one of the best in the field, Precious Kolawole.
The end of a thing is better than its beginning…
-Ecclesiastes 7::8
It’s been one tough ride learning and I’m thrilled of hoe far I’ve come and eagerly anticipating what the final monnth holds.
