“KNOWLEDGE OF SQL IS FAVORABLE, WHEN BUSINESS IS FOR CHAOS STARTING TO LOSE MONEY
Data is the ocean. In order to catch fish in it, and not drown, you need to learn how to select the necessary data in a particular second. The SQL language helps in this business.
Maxim Belko has been engaged in databases for more than eight years. He is now a developer at thredUP, an American IT company. Previously, he worked in the telecom companies Lifecell and Kyivstar. Maxim said why working with databases is a prerequisite for any business, and spy thrillers with a Pentagon hack are fairy tales.
How to use SQL to scale a business
You have an idea: buy watermelons in Kherson and sell them in Borispol. You find wholesalers and the one who brings watermelons, find out the price. Start to sell. Over time, buy trucks and carry watermelons yourself.
Where do you record the contacts of sellers and buyers, data about cars? Most likely in your phone or Google spreadsheet. And if there are dozens of suppliers, buyers and machines? And if you start to carry more melons and flowers? One day there will be too many sheets, and it will be extremely difficult to understand them.
You will need relational databases and something to help structure them. Most often, a business buys boxed solutions with a subscription. But this is a temporary solution. At some point you will want to sell and buy in Belarus, representatives will appear – and you will need to issue different accesses to the system. The boxed solution is not enough.
With such scaling, SQL is needed – it will help to manage the database in which all processes are ordered. Knowledge of SQL is useful when there are not enough leaflets and hands or an order is lost. That is, when a business begins to lose money due to chaos.
What tasks does the database management system solve?
Database Management System (DBMS) – this is what allows you to get information from tables and data files. They are stored on the disk of the operating system, and relational databases help to get them.
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“Relational databases” – a set of tables with data and identifiers. This is similar to the address book: here are the Excel tables – there are the names of the subscribers and numbers that define the city of the subscriber (identifiers 1, 2 … 10). The first tables with names by number refer to the table with the decryption of identifiers – this will make the city clear.
Due to this, instead of one bulky table, we have many small and “light”, interconnected tables. So we reduce the information file size. It takes up less disk space, query execution time is reduced, and the system is faster.
By connecting to the database through an interface or command line, you can change or extract data in a convenient way.
How SQL helps business
In any retail network – Auchan, Walmart, pharmacy chains – many databases. Anyone who needs it can “pull out” and use data using SQL, the structured query language. It allows you to make requests of various types. For example, display a list of checks for yesterday more expensive than a certain amount and see at which ticket offices they were issued.
When a product is bought, brought, sent for storage or sold, the database is updated. You need to be aware of the changes in order to properly respond to them. If chocolate ice cream ends, you can find out about this by contacting the database – and buy it in time.
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Many analysts may have access to the database, but not everyone understands how to write queries to see intermediate results. They cannot compile ad-hoc reports and are awaiting recounts once a week from programmers.
But if the analyst shows the programmers that he knows about HAVING and SUM and knows how to use them, there will be more trust in him, and access will be wider (if the company does not prohibit).
What conclusions about internal processes gives SQL
SQL allows you to “pull out” any data from any business – telecom companies, banks, carriers. But not everyone can do this. To dive into the database, the user must have rights and privileges.
Call, for example, a mobile operator, and there they say: “Hello, Anya.” How do they know your name? It is displayed by phone number. Sound the problem – the operators make a request to the database, receive answers in the interface on the screen.
The answers are “displayed” by the backend, which accesses the database directly and pulls the information itself. He can see how much money was withdrawn, as a result of what action, how this action was combined with others. You can learn about actions only by a specific user – and only what is offered by the administrator or the database.
I am always amused when in spy films someone sits down at a computer and after two minutes says: “That’s it, I hacked the Pentagon.” This does not happen. There are a lot of links in the database – it takes a lot of time to understand where which table is and where what is stored.
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Coming to new projects, you only get to know everything for two months. They say to you: “Here is the main table, five columns.