There comes a point where your organization will outgrow a traditional Spreadsheet as a database. Both Microsoft Excel and Google Sheets are capped at 1 million rows. But does that mean that you stop collecting data or create a new spreadsheet for part 2? No, congratulations, you’ve elevated.
Your next step is organizing your data for import and creating a relational database. Primary keys, foreign keys, tables, joins and using SQL queries are your new best friend; but more on these in another article.
SQL (Structured Query Language) is a programming language that is used to manage and manipulate data stored in relational database management systems (RDBMS). It is a standard language for interacting with database systems, and is used to create, modify, and query databases.
One unique aspect of SQL is that it is a declarative language, which means that you specify what you want to do, rather than how to do it. This is opposite of a traditional high-level programming language like C++ where you have to give explicit instructions. A declarative language makes it easier to write queries, as you don’t have to worry about the details of how the data is stored or how the query will be executed.
One of the most powerful features of SQL is the ability to join tables. This allows you to combine data from multiple tables and view it as a single entity. For example, you could join a table of customer information with a table of orders, and view the customer’s name and order history in a single query.
There are four types of joins:
- Inner Joins: An inner join (aka simple join) returns all rows and columns from all tables queried. This is the standard type of join.
- Outer Joins: There are different types of outer joins but the main idea is to return all rows and columns from one table, along with the unmatched values from the second table.
- Left Joins: The left join takes all rows from the left table and adds all missing rows from the right table. If there is missing data it will return a “null” value.
- Right Join: The right join takes all rows from the right table and adds all missing rows from the left table. If there is missing data it will return a “null” value.
Another important aspect of SQL is the use of indices and keys. Indices are data structures that help the database system quickly locate specific rows in a table, while keys are used to enforce relationships between tables. The two types of keys are Primary Keys and Foreign Keys. Every table must have a unique identifier for each row which acts as a primary key. A primary key in one table will be the Foreign Key in another table, thus creating dynamic relationships. These features help improve the performance of queries and ensure the integrity of the data.
SQL is a powerful and versatile language that is widely used in businesses, organizations, and individuals for managing and manipulating data. Whether you are a beginner or an experienced developer, learning SQL can be a valuable skill to have in your toolkit.
