Relational database systems usually have the same structure. They store data in different databases or schemas, which separate the data from different applications. These schemas are just collections of tables. Tables are definitions of specific data structures and are composed of fields. A field is a basic data type that defines the smallest component of information as though they were the atoms of the data. So, schemas are group of tables that are composed of fields. Let's look at each of these elements.
As defined before, schemas or databases— in MySQL, they are synonyms—are collections of tables with a common context, usually belonging to the same application. Actually, there are no restrictions around this, and you could have several schemas belonging to the same application if needed. However, for small web applications, as it is our case, we will have just one schema.
Your server probably already has some schemas. They usually contain the metadata...