what are the basic features of the relational data model?
438714
The basic structures of a relational database (as defined by the relational model) are tables, columns (or fields), rows (or records), and keys. This section describes these elements.
881224
The main difference between hierarchical network and relational database model is that hierarchical model organizes data in a tree-like structure while network model arranges data in a graph structure and relational database model organizes data in tables.
393775
When you design a database, you divide your information into tables, each of which has a primary key. You then add foreign keys to related tables that reference those primary keys. These foreign key-primary key pairings form the basis for table relationships and multi-table queries.
1078297
['Real World Entity. DBMS these days is very realistic and real-world entities are used to design its architecture. ... ', 'Self-Describing Nature. ... ', 'Support ACID Properties. ... ', 'Concurrent Use of Database. ... ', 'Insulation Between Data and Program. ... ', 'Transactions. ... ', 'Data Persistence. ... ', 'Backup and Recovery.']
1287733
['a collection of logically related shared data.', 'n the data is split into a number of fragments.', 'fragments may be replicated.', 'fragments/replicas are allocated to sites.', 'the sites are linked by a communications network.', 'the data at each site is under the control of a DBMS.']
808121
['Query Decomposition. The first layer decomposes the calculus query into an algebraic query on global relations. ... ', 'Data Localization. The input to the second layer is an algebraic query on global relations. ... ', 'Global Query Optimization. The input to the third layer is an algebraic query on fragments. ... ', 'Distributed Query Execution.']
201945
['Hierarchical database model.', 'Relational model.', 'Network model.', 'Object-oriented database model.', 'Entity-relationship model.', 'Document model.', 'Entity-attribute-value model.', 'Star schema.']
1191210
['Table – Basic unit of storage; composed rows and columns.', 'View – Logically represents subsets of data from one or more tables.', 'Sequence – Generates primary key values.', 'Index – Improves the performance of some queries.']
357218
An RDBMS is a DBMS which manages a relational database. A relational database stores data in tables. Tables are organized into columns, and each column stores one type of data (integer, real number, character strings, date, …). The data for a single “instance” of a table is stored as a row.
228401
The conceptual model is to establish the entities, their attributes, and their relationships. The logical data model defines the structure of the data elements and set the relationships between them.
45411
['A data field holds a single fact or attribute of an entity. ... ', 'A record is a collection of related fields. ... ', 'A file is a collection of related records. ... ', 'Files are integrated into a database.']
1136085
['Excellent for handling data with a complex structure or atypical data.', 'Data described using markup language.', 'Text data description.', 'Human- and computer-friendly format.', 'Handles data in a tree structure having one-and only one-root element.']
75361
['Improved data sharing: The DBMS helps create an environment in which end users have better access to more and better-managed data. ... ', 'Improved data security: ... ', 'Better data integration: ... ', 'Minimized data inconsistency: ... ', 'Improved data access: ... ', 'Improved decision making:']
735389
['Represent entities.', 'Represent relationships.', 'Normalize the relations.', 'Merge the relations.']
960712
A conceptual data model identifies the highest-level relationships between the different entities. ... A logical data model describes the data in as much detail as possible, without regard to how they will be physical implemented in the database.
444563
['Platform Functions. These features establish a baseline for the system to operate around. ... ', 'Data Visualization. Once data is organized in a data warehouse, it is ready to be visualized. ... ', 'Analytics. ... ', 'OLAP. ... ', 'Document Management. ... ', 'Decision Services. ... ', 'Integrations.']
298418
['Advantages of Database. 1) Data Abstraction: 2) Controlling Data Redundancy: 3) Minimized Data inconsistency: 4) Data Manipulation Easily: ... ', 'Disadvantages of Database. 1) Cost of Hardware and Software: 2) Cost of Data Conversion: 3) Cost of Staff Training:']