Magento Core Tables
1) eav_attribute
whenever you create a attribute this table gets entry which stores all important data which helps to make a relation, like entity_type_id,attribute_code,backend_type and many more but this are the important fields.
2) eav_entity_type
Magento has 8 types of entity, by which, type of attribute is decided. in your case it is catalog_product
1) customer
2) customer_address
3) catalog_category
4) catalog_product
5) order
6) invoice
7) creditmemo
8) shipment
catalog_product_entity is the primary table for product, our product id is nothing but a value of entity_id of this table.