SQL Databases

Introduction

Spreadsheets are a thing of the past ! If you have large amounts of data, you probably store them in various database formats. These databases are essential, because they let you store, modify, and consult information.

However, there are many types of databases that offer different functions and characteristics. When you want to conserve similar information in a clear structure, the best format is SQL databases.

This article goes through the important aspects of SQL databases and explains how to use these databases efficiently.

The basics of SQL databases

What is an SQL database?

A database is a set of information that is gathered under a specific structure. This base has a management system, enabling access to the stored information.

There are multiple types of databases, including relational SQL and NoSQL databases. SQL databases keep information in tables:

• Each row represents a dataset that relates to, for example, the same client or same transaction. All data on a row is related, which is why the database is called relational.
• Each column represents a category of the dataset. One of these columns shows the primary key of the set, a unique identifier to help find the set.

To better visualise this system, here is an example of an SQL table where customer information would be stored. The coloured line represents a dataset, classified according to the category in each column.

Customer ID (primary key)	Surname (sequence of letters)	Name (sequence of letters)	Age (whole number)	Department (whole number)
C6789	Smith	Henry	35	75
C6790	Johnson	Chloe	28	59
C6791	Beckett	Helen	42	75

The benefits and disadvantages of SQL databases

Benefits

SQL databases are relatively intuitive and easy to understand, and they store information grouped by complex lints. Moreover, they are a stable storage method, thanks in great part to primary keys.

It is also possible to combine tables quickly and easily, because of primary keys. Using the previous example, you can group your customer table with the table below, by using the “Region” primary key. This key lets you attribute a closest delivery point to each customer. 

Region(Primary key)	Closest delivery point
Greater London	London
Southwest	Bristol

Disadvantages :

SQL databases have a precise structure that isn’t flexible. Stored data must be already clean and in the format imposed by each column.

This structure also limits the storage space; SQL databases are quickly overwhelmed in situations with large amounts of data (big data). 

Finally, these databases require a level of expertise with SQL, meaning that you will have to learn the syntax.

SQL database use cases

SQL databases have quite specific use cases. This method is effective when:

• The relations between data are well-defined, which maintains a clear structure for the SQL database.
• You know which types of data to store (the categories in the columns), and when they don’t vary a lot.
• You wish to regularly modify specific points in the database.
• You don’t have a large amount of data.

If you choose to work with SQL databases, you need to choose between many database management systems. These are commonly known as “versions of SQL databases”. The most popular are MySQL, SQL server, PostgreSQL, and Oracle SQL.

Basic SQL database commands

The main commands

To use SQL database management systems and to send through queries (i.e. interrogate them on stored data), you have to use SQL (Structured Query Language). 

The SQL you may use will vary depending on the chosen management system, but it is a relatively simple programming language. It works with some classic commands. SQL has multiple sub-languages, based on what you want to do.

Here are some of the commands to know for the main sub-languages:

• To define and add data — Data definition:

✅ CREATE : create a table.

• To manipulate and modify data — Data manipulation:

✅ INSERT INTO : add a row to a table.

✅ UPDATE : modify existing rows.

✅ DELETE : remove one or multiple rows

• To interrogate the database — Database interrogation:

✅ SELECT : choose only the columns that you want to view or modify. It is THE essential SQL command!

Best practices to use SQL commands

To use SQL commands properly, and to code in general, it is best to follow these steps :

1. Precisely define your objective and what you want to obtain.
2. Think about the relevant steps to attain this goal, according to the shortest possible goal. 
3. Transcribe these steps with the relevant SQL commands.
4. Perform tests with simple tables that make it easy to check your code.

To have successful 2nd and 3rd steps, you need to know SQL database commands and what they let you do. It is also important to be familiar with common commands like AND and OR, and commands to enter conditions, such as WHERE.Finally, depending on your goals (step 1), you will use SQL differently. If your goals are repetitive and similar, you should learn the relevant SQL commands in detail, so as to code more quickly.

Also, choose a single management system, in order to use the same procedures as much as possible.

Tools and technologies to help code in SQL

To code well in SQL, you need to have some basic knowledge and be comfortable with the main commands.

You can then get help from online communities, like those on Reddit, Github, or Stack Overflow. If you have a question, you’ll probably find the answer online! Don’t hesitate to use the Internet for your research.

There are also many services that exempt you from coding. You just need to state your goals or your steps, and the software will give you the appropriate SQL code. You can do this with ALLONIA’s platform: our no code solution will help you in your SQL coding project. 

Challenges with managing SQL databases

Data protection

Issue: whenever data is stored, security becomes an issue. It is vital to protect data from potential cyber attacks, whilst maintaining easy access to users.

Consequence: data protection can be very expensive and time-consuming. However, it is essential for any company, a legal obligation in fact.

Solutions: many experts have data protection solutions. ALLONIA offers, for example, a high level of security and hosts your data on European servers. Our services make it easy to manage user groups and their access to data.

Scalability

Issue: as mentioned above, SQL databases require that the data loaded and added vertically actually matches the structure of the tables.

Consequences: you need to write time-consuming requests to add new data, limiting the scalability of this method.

Solutions: so that your system still works when the amount of data increases, you should prepare recurring procedures. These can be set up with an expert or with software to help you manage complex procedures and guide your data. This is what ALLONIA offers, for example.

However, if you expect a high increase and a change in the type of data, SQL databases are probably not suited to your needs.

Maintenance

Issue: SQL databases require maintenance and repetitive management tasks, like backups, updates, or cleaning to remove empty rows.

Consequence: as you can imagine, these tasks take time and stop your qualified employees from focusing fully on development missions.

Solution: you can automise this process, with maintenance assistants offered by management systems. These tools are often criticised, however, so you may also have to use additional software. 

Conclusion

You now know the basics of SQL databases, their use cases, and the potential problems to be aware of.An awareness of these basics will help you manage these databases more efficiently, so it is essential to prepare beforehand. If you need help to exploit your data efficiently, contact us today.

At ALLONIA, we help companies jump on the AI bandwagon! Our teams of experts will help you to industrialise AI in your sector of activity, whatever it may be: energy, mobility, logistics, cybersecurity, healthcare, commerce, banking, insurance, tourism, etc.

We’ve developed a secure, federative, simple and sovereign all-in-one platform for large companies, SMEs, ETIs and public organisations, so you can manage your business issues with your technical and business teams.