How to set schema validation rules for fields in a project for MongoDB

In Moon Modeler, you can easily design MongoDB database structures and generate scripts for schema validation. Many schema validation rules are accessible directly in the user interface, and additional rules can be defined textually.

Let’s see how to set the validation to the minimum and maximum value, for example. As an example, let’s use the “students” collection, in which we have defined the fields “name“, “year” and “major“.… Read the rest

MongoDB vs PostgreSQL

Making a comparison of document-based database systems like MongoDB and traditional relational databases like PostgreSQL is not a simple task. In fact, it is impossible to recommend one database platform, because everything depends on your requirements and the goals you wish to achieve. For some use cases, MongoDB can be the preferred solution, for many other use cases PostgreSQL can be the better option.… Read the rest

Primary key vs unique key

What is the difference between primary and unique keys?

What primary keys are and what they are used for is explained in the article describing the difference between primary and foreign keys.

A short summary: Primary keys serve as the identifier of a unique record, it can be unique information, such as a driver’s license number, telephone number including area code, car VIN number, etc.Read the rest

Primary key vs foreign key

What is the difference between primary and foreign keys in relational databases?

Primary keys serve as the identifier of a unique record in a database table. It can be unique information, such as a driver’s license number, telephone number including area code, car VIN number, etc.

 

Primary key - driving license
CREATE TABLE `ecommerce`.`customer` ( 
   `driving_license` VARCHAR(100),
   `name` VARCHAR(150) NOT NULL,
   `surname` VARCHAR(150) NOT NULL,
   `email` VARCHAR(150),
   `phone` VARCHAR(200),
    PRIMARY KEY `Primary key`(
   `driving_license`
    )
)
 ENGINE = InnoDB;

Multi-column primary keys

A primary key can contain one or more columns.Read the rest