For classified objects of the same type and level, the code has a sorting function. Each entity set and relationship set in the database is associated with a unique table, and the table name is the name of the entity set and relationship set. Each table consists of several columns, and the table and table attribute columns must be clearly defined. This definition information is an important part of the database's data dictionary. When the value of the attribute column in the table is coded, the meaning of the code should be clear and there should be no inconsistencies or conflicts. Therefore, coding should have a clear design and formulate unified coding standards to facilitate subsequent database management and management. maintenance and information sharing and exchange are ensured.
Usually, coding design follows certain principes. Under the guidance of these principles and in combination with the existing classification coding system, the specific coding design of the data integration platform is carried out.
3.1.3.1 Principles of formulation and use of codes
(1) Wherever national standards and industrial standards exist, national standards and industrial standards shall be used, such as administrative division codes, Chinese rivers name code, etc. ;
(2) Where no national or industry standard exists, the code standard used in this system shall be formulated;
(3) Where the standard is formulated, like other databases If code already exists, consistency should be considered, and the code should use existing code or modify it as much as possible based on existing code
(4) The code must be unique, and each coded object must have only one code, a code does not identifye only one coding object;
(5) Relative stability, the number of digits in the code. must leave room for coding, so that no major changes occur over a long period of time;
(6) completeness and scalability Coding must be able to reflect the attributes of the elements and the from each other. relationships between elements in a relatively complete manner, while allowing appropriate room for expansion in the coding structure.
(7) Mandatory. In principle, the use of the code should be mandatory. All ocean data that must be recorded and integrated on this platform must follow design standards. Data using other standards can be efficiently recorded and integrated after transforming the platform code standard.
3.1.3.2 The data coding design and standard marine information grid platform mainly involves datadata, including remote sensing data, vector data (including basic coastal and offshore geographic data, comprehensive survey atlas data on coastal areas and tidal plains, coastal land use and marine functional zoning, etc.) and observation data. Among them, remote sensing data and observation data do not have high coding design requirements, while vector data has relatively high coding design requirements. Mainly because vector data for coastal areas and offshore waters includes data from land-based research departments and data from marine institutions. The original data itself has coding inconsistencies. In addition, due to the inconsistent concept of coastal areas in various areas, different industries have different standards of clinconsistent assification for the same objects, resulting in coding inconsistencies. These issues not only impose high requirements on coding redesign, but also pose challenges for final data integration.Here's the problem. In this section, the main focus is on the first point.
In coastal and offshore vector data, the coding of basic geographic data and the coding of coastal land use currently adopt national standards. The former primarily uses 1:1 million and 1:250,000 national topographic maps, the latter using standard Department of Land and Resources land type coding. Furthermore, in terms of classification codes in the maritime domain, there are already national and industrial standards: classification and codes of elements of topographic maps 1:500, 1:1000, 1:2000, classification and codes of informationThematic map mations, Chinese navigation map format. , Classification and coding of marine biological resources population data, classification and coding of marine biological environment, etc.