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Introduction to Databases

In this step, we'll be introduced to relational databases at a high-level and look at what sets them apart from simply storing data as a file.

In this step, we’ll look at relational databases at a high-level and what sets them apart from simply storing data as a file.

A system for storing data

Traditional databases are systems for storing data in a predetermined and organised manner, following a tabular schema. In other words, there are rows and columns. The columns have headers that tell you what the content of the cell should be referring to, and each row is a unique record.

Relational data

Many databases are not single tables, but multiple tables that have related information. To reduce the size of individual tables, a process known as normalisation is performed.

Through the use of SQL, you can draw related information from multiple tables as required, but store the information separately to maintain organisation and reduce unnecessary bloating.

Primary keys and foreign keys

Primary keys are columns in a table that are used to uniquely identify a record. This can be something generated manually when you know no other row in the table will be assigned the same value, or can be taken from existing data.

Examples of this in everyday life are identity (ID) or passport numbers, email addresses, or bank account numbers.

Foreign keys are a column (or group of columns) that are unique values in a record/row that tie that record to another table, associating it with another unique record/row in another table in the same database.

Relational database vs semi-structured or hierarchical files

The dependency and interrelation of data within a relational database are what gives the format its value when compared to semi-structured data such as JSON or XML files, which can generally not inherently relate their data to the data found in other files.

In the next step, we will take a closer look at how we can build a relational database.

Join the discussion

What would drive you to choose a relational database over file stores such as JSON or XML?

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