database schema

There are three schemas in the database [☆Three-level Architecture☆]: external schema, conceptual schema and internal schema.
    The external mode is at the user level, also known as the user view (VIEW), which is closest to the user and is the logical structure of the part of the data that a single user sees and is allowed to use; the conceptual mode is the overall logical description of the data of all users of the database, Includes logical record types and relationships between records; intra-schema is at the physical level, also known as storage schema.
    Generally, the outer schema corresponds to the view of SQL , the schema corresponds to the basic table, the tuple is called "row", the attribute is called "column", and the inner schema corresponds to the storage file.
    The "pattern" you said should refer to the external pattern. We generally have two levels of abstraction for the information of the external world. In the first level, we use the ER diagram to describe the pattern of each entity. In the second level, we will describe the entity pattern using It is represented in the form of a database, so it is also called a data schema. Let me give you an example of a simple first-level relational model: students (study, name, gender, age), of course , the performance at the data level with SQL is not like this