Database schem is a definition or description (Description) of the database that contains the definition of the database structure and the internal database schema should be based on the overall view of how to store the data in a reasonable level whether it is six. the format and structure. How data is stored, which is responsible for storing information in memory.Conceptual schema is the degree of the relationship of the data view in the database that contains the information store? Are related to other data, including different rules?External schema or view window (View) external users are entitled to use the view (View) is part of the General information that users are interested in and have access rights apply.Independence freedom of information data (Data Independence).Can be divided into 2 types: 1. commercial-physical data independence (Physical Data Independence) is a change in level within the structure would not affect the conceptual level structure and an external level, for example, to change the way the information from the original to run more efficiently. It will not affect the conceptual level or user level 2. independence of the commercial information (Logical Data Independence), tak is to change the information on the conceptual level. It will not affect the structure of the external level, such as Add. Field, or a new table into a database. DDL (Data Definition Language), or a language for defining the structure and management of the database is in a language that is intended for a particular database handle is. Create, edit, or delete a database, database.DML (Data Manipulation Language) is a language for data stored in the data table in which the DML languages will cover all data manipulation, such as add, edit, search, and delete data.Query language is a computer language that is used for the query or deal with data in DBMS.Host language is a language that is embedded in other languages.1 database utility to reduce redundant data storage Some data sets are in the form of a data file might appear different because there are many users of this information. When you use the database system and will help. Duplication of data, less 2 maintain the accuracy of the information, because the database contains only one database, in case the same information appears in the database. This information must match. If there is a. Edit this data, the data displayed will be for every edit, as per all. 3 database management system and data security. The protection and security of the information system, the database, only those that are relevant. Which produces a number of information security (security).Catalog listArchitecture client/server Application Program is working to share by any User, it will be close to the Client-side Presentation logic and Application logic, such as best Server-related tasks, such as Data storage and Data access logic is in the Server side.One of the middleware architecture consists of a three-tier Client, Middleware, Database Server, or other Server Appliaction.N-tier one of the middleware consists of architecture., Client Server, Database Server at work. Divide the burden sometimes are made in 2. Appliaction Logic.
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