• Data-collection of the version of the tool that the concepts for describing data, data relationships, the meaning of the data, and the limitations of the stability-the data format provides a way to describe the design of the database at the logical and physical views. • Data network • model hierarchical data model Entity-relationship model relationship thot • object based on the data structure of a half version of •individual. • Database Schemas:-overall design of the database.• Internal schema -Describe the physical storage structure of the database. -Describes all the details of the storage and access to the database. • Conceptual schema -Describe the structure of a database for the user community.-Hide the details of the structure, physical storage, and focuses on the description of the data type of agency relationship of the user's operations.And restrictions.• External schema.-Each external schema describes the part of the user groups in particular are interested in and hide the rest of the database from the users group.• Freedom of information The ability to change the schema in the database without needing to change the schema at the next higher level. • DDL -To identify the blend came to databases-DDL's exports has been placed in the dictionary that contains metadata. -That is, data about data. • DragonTo display the tracing database and updates.• Questionnaire languag Computer programming languages that are used to retrieve data from the database.The database management system that provides programmersThe view represents an expansion of the existing program.Makhae catalog data, statistical and other physical data, and create a code of practice that have performance that is needed for the search, and make a line in the run-time processing.
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