An attribute-value system is like a special kind of library where each book has a tag on it that tells you something about the book. Imagine you have a toy box, and every toy has a tag on it that tells you its name, color, and shape. This is just like the attribute-value system.
In computers, an attribute-value system is a way of categorizing information. Different features, like the size, color, price, or type of information, are called attributes. Each of these attributes has a value associated with it, like "large," "red," "expensive," or "picture."
For example, let's say you have an online store that sells t-shirts. You could create an attribute-value system using details like the size, color, price, and type of fabric for each shirt you sell. This way, a customer can easily find the shirt they want because they can search by one or more of these attributes.
Overall, an attribute-value system is just like a library for data, making it easy to sort and find things based on their attributes.