Blur database
Refers to a database that can handle blurred data. The general database is based on two direct logic and precise data tools, and it cannot represent many vague.
thing. With the establishment of the fuzzy mathematics system, people can use the quantity to describe the fuzzy events and can perform a fuzzy operation. This will make incomplete, uncertainty
Qualitative, fuzzy introduces in the database system to form a fuzzy database. There are two main aspects of fuzzy database research, first of all, how to store blurring in the database
Data; followed by defining various functions on fuzzy data. The representation of the fuzzy number mainly has a blurred section, the number of blurred center, the number of blur collection and the membership letter
Number.
Statistical database
Manage statistics database systems. Such databases contain a lot of data records, but their purpose is to provide users with various statistical summary information instead of
Provide information on a single record.
Net database
Processing a database of a network data model with a node with a record type. The treatment method is to decompose the mesh structure into several secondary tree structures, called the system. Type
It is a description of the connection between two or more record types. In a system type, there is a record type being dominated, called the main record class.
Other, other, called member records. The connection between the main and members is a couple of contacts. The representative of the mesh database is a DBTG system. 1969 USA
Codasyl organization proposes a "DBTG Report", which is generally referred to as a DBTG system according to the DBTG report. Existing network database system
It is a DBTG scheme. The DBTG system is a typical three-level structural system: submodel, mode, storage mode. The corresponding data definition language is called sub mode set, respectively.
Language SSDDL, Mode Definition Language SDDL, Device Media Control Language DMCL. There is also a data manipulation language DML.
Deductive database
Refers to a database with interpretation. In general, it is implemented with a database management system and a rule management system. The number of facts that will be reasonably used
According to the database, it is called an extension database; the fact that the logical rules define the fact that the derived must be exported is called a connotation database. The main research content is how effective
Counting logic rules reasoning. Specifically: the optimization of recursive queries, consistency maintenance of rules.
