Database Instance Metadata Data Constraints Query Data Manipulations Database Engine DATABASE SCHEMA A database schema is a sketchskeletonblueprint of a planned data It represents the design of table ID: 1029311
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1. DBMS Key ConceptsDatabase SchemaDatabase InstanceMetadataData ConstraintsQueryData ManipulationsDatabase Engine
2. DATABASE SCHEMAA database schema is a sketch/skeleton/blueprintof a planned data. It represents the design of table columns, relations, constraints and relationshipsthat make up a logically distinct section of adatabase.
3. DATABASE INSTANCEA database instance is a snapshot of a databasethat exists at a particular time, i.e. the data which is stored in the database at a particular momentof time.
4. METADATAMetadata refers to data about data. Metadatais stored in Data Dictionary.DATA DICTIONARYA data dictionary contains metadata such as the definitions of all schema objects in the database (tables,views,indexes,and all other database objects) along with information.
5. DATA CONSTRAINTSData stored in a database must fulfill some rules and conditions so that only validated and required data is stored. The rules andconditions of data are defined via DataConstraints. A database constraint is a set of rules that define valid data. They are NOT NULL, PRIMARY KEY, UNIQUE, CHECK, DEFAULT, FOREIGN KEY.
6. QUERYA query is a type of command that retrieves data from a database stored on a server. A database query is usually written in SQL ( Structured Query Language)- a specific type of language created specifically for queries.
7. Data manipulationData manipulation is the result of action. Data Manipulation takes place when the data in tables is inserted, updated or deleted.
8. RelationAL Database ModelIn relational data model, the data is organized into tables (i.e., rows and columns).These tables are called relations. A row in a table represents a relationship among a set of values. Rows of relations are generally referred to as tuples and the columns are usually referred to attributes.
9. Relational Database Management System The relational model was propounded by E.F. Codd of the IBM. Examples of Relational Database Management Systems include oracle database, Microsoft SQL Server, MYSQL, IBM DB2, IBM Informix, SAP Sybase, Adaptive Server Enterprise, PostgreSQL, SQLite etc.
10. Components of a TableByte: A byte is a group of eight bits and is used to store a character.Data Item: A data item is the smallest unit of named data. A data item represents one type of information is known as field.Record: A record is a row or named collection of data items of a person.Table: A table is a collection of rows and columns.
11. RNONAMECLASSHOUSEMARKS1101AASTHAXIIBLUE981102AKSHATXIRED781134RAGHAVXYELLOW991158SUHANIIXGREEN861160YUTIKAVIIIRED99Require 6 bytesRecord of a personFields/Columns/AttributesTuple: Rows of a tableAttributes: Columns of a tableDegree: The number of columns of a table(5)Cardinality: The number of rows of a table(5)