Реферат тақырыбы: The conceptual, logical and physical data models
Characteristics of a Logical data model
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- Бұл бет үшін навигация:
- Physical Data Model A Physical Data Model
- Characteristics of a physical data model
- Advantages and Disadvantages of Data Model: Advantages of Data model
| Characteristics of a Logical data model
Describes data needs for a single project but could integrate with other logical data models based on the scope of the project. Designed and developed independently from the DBMS. Data attributes will have datatypes with exact precisions and length. Normalization processes to the model is applied typically till 3NF. Physical Data Model A Physical Data Model describes a database-specific implementation of the data model. It offers database abstraction and helps generate the schema. This is because of the richness of meta-data offered by a Physical Data Model. The physical data model also helps in visualizing database structure by replicating database column keys, constraints, indexes, triggers, and other RDBMS features. Characteristics of a physical data model: The physical data model describes data need for a single project or application though it maybe integrated with other physical data models based on project scope. Data Model contains relationships between tables that which addresses cardinality and nullability of the relationships. Developed for a specific version of a DBMS, location, data storage or technology to be used in the project. Columns should have exact datatypes, lengths assigned and default values. Primary and Foreign keys, views, indexes, access profiles, and authorizations, etc. are defined. Advantages and Disadvantages of Data Model: Advantages of Data model: The main goal of a designing data model is to make certain that data objects offered by the functional team are represented accurately. The data model should be detailed enough to be used for building the physical database. The information in the data model can be used for defining the relationship between tables, primary and foreign keys, and stored procedures. Data Model helps business to communicate the within and across organizations. Data model helps to documents data mappings in ETL process Help to recognize correct sources of data to populate the model жүктеу/скачать 23.78 Kb. Достарыңызбен бөлісу:
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