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What does a database schema imply? What are its types? |
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Answer» A "database schema" is a plan for how a database is built that describes how data is ORGANIZED (DIVIDED into database tables in the case of RELATIONAL databases). A database schema is formally defined as a series of formulas (sentences) known as integrity constraints that are imposed on a database. Physical schema, logical schema, and view schema are the three types of schema. The physical schema describes how the data contained in blocks of storage is characterized at the physical level of a database. The logical schema is the design of a database at the logical level; programmers and database administrators work at this level; data can be characterized as certain types of data records that are stored in data structures; however, internal details such as data structure IMPLEMENTATION are obscured at this level (available at the physical level). View schema is the design of a database at the view level. This term refers to how end-users interact with database systems. |
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