Understanding of data elements and metadata (very useful)

The data element is the data unit, is the smallest unit of the industry domain data

Metadata is the data that describes the data, and if there are 10 properties of the data element, then these 10 attributes are the metadata of the metadata.

The object is relatively fixed, and the metadata depends on the data entity it describes, which is relative, and becomes the entity's metadata when it is used to describe its parent composite entity.

The core metadata is a set of metadata that has the same value for a group of homogeneous entities.

Extended metadata is a set of metadata with different values for a homogeneous entity.

Table, which is the storage of a group of homogeneous entities

The same kind is the class, the entity is the object

Take a student registration form as an example, the form above is the basic information of students, name, school number, class, the form below is a list of students to hold the course information, class number, name, credit. For this form, the database is designed into 2 tables, one is the Student basic information table, and the other is the Student selection information table.

Names, school numbers, classes, courses, credits are data elements, these data elements have their own metadata, that is, the description of data, respectively, length, type, range, and so on.

For the Student Basic information table, the name, school number, class is the data that describes the basic information of students, is its metadata.

For the students to choose the course Information table, the course number, name, credit is to describe the Student selection information table data, is its meta-data.

Each record in the table is an entity, and the abstract of the table is a class.

Whether it is a student information table or an elective information table, there is a description of the storage location, and all the data in a table is stored in the same location, that is, the basic properties of the class, this basic property we become the core metadata. Core metadata is an entity that is common to all classes in an industry, and that all entities of a class have the same value.

Extended metadata is a property that is unique to each class relative to the core meta-data. The previous name, school number, class, course number, name, and credits are all extended metadata.

Reproduced:

Http://www.educity.cn/blog/user2/53043/archives/2013/51350.html

Understanding of data elements and metadata (very useful)