Why create and use "child databases" within databases ?
For specific use cases, it is important to create a distinction within the same database of elements.
If you want to separate an element database in two, you will have to create two child databases.
What is a child database within databases ?
Ermeo allows you to create databases of elements. All the elements present in the same database will have the same attributes.
In a database, one can define child databases also called "sub-databases".
In this case, there will be an inheritance of attributes. The existing attributes for the database will also exist for the child databases.
In practical, how to create child databases ?
Context : Imagine a company that inspects thousands of rails across Europe. These rails are elements stored in a database called "Rails".
Each element of the database will be characterized by the following attributes:
- Rail length
- Rail thickness
- Year of Rail
The company wants to add an attribute to qualify the rail standard. This standard is not the same between France and England.
We are going to create a first child database named "Rails England". This child database will have the attribute "England Standard".
Then, we will create a second child database named "Rails France". This child database will have the "France Standard" attribute.
1. In the Assets tab, click on the toothed wheel then on Families.
2. Create a new database. Name it "Rails".
3. Create and add the following attributes:
- Rail Length (Number type)
- Rail thickness (Number type)
- Rail year (Number type)
4. Click on Validate.
5. Stay on the Families page and select the newly created "Rails" database.
6. Click on "Create a sub-family". The name will be "Rails France". Add a multiple choice attribute and name it "France Standard".
Enter the following values for the multiple choice:
- NF 1435 mm
- NF 1700 mm
7. Repeat step 6, replacing the term France with England. Enter the following values for the multiple choice :
- NUK 1524 mm
- NUK 1628 mm
You have created your two subfamilies "Rails France" and "Rails England". These two sub-families appear in the "Rails" database.
You can now create elements in each of the sub-databases.
- The elements created in the "Rails England" subfamily will have the attribute "England Standard.
- The elements created in the "Rails France" subfamily will have the "France Standard" attribute.