Graph data model and its data language
Complex databases can be understood well with visual representation. A graph is a very intuitive and rational structure to visually represent such databases. Graph Data Model (GDM) proposed by the author formalizes data representation and operations on the data in terms of the graph concept. The GDM is an extension of the relational model toward structural representation. In this model, a database is defined by a schema graph where nodes represent record types and arcs represent link types that are relationships between two record types. The capabilities of the GDM include direct representation of many-to-many relationships and of the relationships within a single record type. The characteristic operators are those associated with links: existential, universal, numerical and transitive link operators. Graph Data Language (GDL) is a data language based on this GDM. The essence of the GDL is path expressions used for formulation of queries. The concepts of GDM and GDL have actually been implemented by Ricoh Co., Ltd. and a system based on these concepts is commercially available for many UNIX machines.
What people are saying - Write a review
We haven't found any reviews in the usual places.
Implementation of GDL
A Comparison of Access Path Strategies
1 other sections not shown
Other editions - View all
algebra ASGNRL attr attribute name B*-tree CALLED FROM CALLS CODASYL constraint definition cost Data Definition Language data language Data Manipulation Language data structures database database management systems DBMS def list defined definition table delete denotes DML statement Downward mode Elementary Data Operations EMPLOYEE ENROLLMENT Entity-Relationship model ENTRY ON EXIT execution existential link operator EXIT ALGORITHM CALLED GETREC implementation inter-record restriction link name link occurrences link storage link type LTYP1 node record type numerical link operator occurrence file OPERAND_RLTYP1 PARAMETERS ON ENTRY path expression pointer precompiler primary key Procedure PURPOSE PARAMETERS query processing record and link record clause record list type record name record occurrences relational algebra relational model resultant record list retrieved RLPROJ RTYP1 RTYP2 run-time procedures run-time system schema definition search key select record selection expression specified SRCHTRE storage operations target record type terminal node record transitive closure URI-array volatile