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What is the difference between database instance and relation schema?
Database Instance The term instance is typically used to describe a complete database environment, including the RDBMS software, table structure, stored procedures and other functionality. It is most commonly used when administrators describe multiple instances of the same database.Also Known As: environment Examples: An organization with an employees database might have three different instances: production (used to contain live data), pre-production (used to test new functionality prior to release into production) and development (used by database developers to create new functionality). RELATION SCHEMA A relation schema can be thought of as the basic information describing a table or relation. This includes a set of column names, the data types associated with each column, and the name associated with the entire table. For example, a relation schema for the relation called Students could be expressed using the following representation: Students(sid: string, name: string, login: string, age: integer, gpa: real) There are five fields or columns, with names and types as shown above.
What is the difference between catalog schema and database in SQL Server?
A catalog is simple a group of related schema collected together in a defined namespace. While schema is a group of one or more related object collected in a common namespace.
What is the difference between data model and schema in database?
As I understand it, a database schema is a physical entity, it describes the structure of exactly how the data is stored and is itself stored by DBMS for reference. Data model, on the other hand, is an abstract representation of database.
What is the difference between relation and table in data base?
Table is where the data is stored and in a well designed schema a table represents some real world object such as CUSTOMER, ORDER, etc., Now the real world objects have relationships. For example, a CUSTOMER has many ORDERS. To represent this relationship a database relationship was invented.
What is the difference between derived attribute and normal attribute?
A normal attribute is an attribute present in a schema and which has to be entered while entering a tuple.A derived Attribute is one which can be inferred(derived) from another normal attribute and it need not be a part of a schema.For e.g.-> In a schema, Date-of-Birth is a normal attribute.While Age is a derived attribute which can be derived from the Date-of-Birth
Difference between schema sub schema and instance in DBMS in detail?
the overall logical data base description is referred to as a schema. it is sometimes also referred to as an overall modal of the data, a conceptual modal of the data, a conceptual schema
What is schema and sub-schema?
The schema is the physical arrangement of the data as it appears in the DBMS. The subschema is the logical view of the data as it appears to the application program.
What is the difference between database instance and relation schema?
Database Instance The term instance is typically used to describe a complete database environment, including the RDBMS software, table structure, stored procedures and other functionality. It is most commonly used when administrators describe multiple instances of the same database.Also Known As: environment Examples: An organization with an employees database might have three different instances: production (used to contain live data), pre-production (used to test new functionality prior to release into production) and development (used by database developers to create new functionality). RELATION SCHEMA A relation schema can be thought of as the basic information describing a table or relation. This includes a set of column names, the data types associated with each column, and the name associated with the entire table. For example, a relation schema for the relation called Students could be expressed using the following representation: Students(sid: string, name: string, login: string, age: integer, gpa: real) There are five fields or columns, with names and types as shown above.
What is difference between Schema and Subschema?
SCHEMA is the physical arrangement of the data as it appears in the DBMS. SUB-SCHEMA is the logical view of the data as it appears to the application program.
What is Schema in the term of Database Management System?
Schema means structure of the databse. Like, tables, constraints, relation
Describe the differences in meaning between the terms relation and relation schema?
Relational Schema refers to meta-data elements which are used to describe structures and constraints of data representing a particular domain. Whereas a relation is a property or predicate that ranges over more than one argument Here's some translation from "Relational Algebra" to SQL terminology: * "Relation" = Table. * "Relation Schema" = Table definition. So for example, the "schema" for the Person "relation" is: Person(FirstName, LastName, Age, Gender, Address) Also in relational Algebra, a "tuple" is a table row, and an "attribute" is a table column.Mathematician define a relation to be subset of cartesian product list of domains.In daabase relation is a set of entities with similar attributes.In other way we can consider a relation as a table and it's rows as entities, and table's columns as attributes.Concept of relation corresponds to programming language notion of variable.relational Schema corresponds to the programming language notion of type definition.It is the logical design of database.e.g. for a relation account having attributes account_number, branch_name and balance, relational schema is specified as -Account_schema= (account_number, branch_name, balance)
What is the data schema in a database?
Logical Structure of database is know as database schema. All database entities are defined and relation between then is represented in structured way. It includes all constraints to be apply on each identity.
What relation and relation schema?
Relational Schema refers to meta-data elements which are used to describe structures and constraints of data representing a particular http://wiki.answers.com/Describe_the_differences_in_meaning_between_the_terms_relation_and_relation_schema#. Whereas a relation is a property or predicate that ranges over more than one argumentHere's some translation from "Relational Algebra" to http://wiki.answers.com/Describe_the_differences_in_meaning_between_the_terms_relation_and_relation_schema#terminology:"Relation" = Table."Relation Schema" = Table definition.So for example, the "schema" for the Person "relation" is: Person(FirstName, LastName, Age, Gender, Address)Also in relational Algebra, a "tuple" is a table row, and an "attribute" is a table column.
Why do you need mapping between schema levels?
There is need for mappings between schema levels for visualization and schema matching. The mappings between schema levels helps in the different types of transformation.
What is the difference between catalog schema and database in SQL Server?
A catalog is simple a group of related schema collected together in a defined namespace. While schema is a group of one or more related object collected in a common namespace.
Difference between star flake schema and star schema?
STAR SCHEMA ::contains dimension tables mapped around a fact table. it is a de normalised model.no need to use complicated joins.queries results fastly. @ahsan_ravian@hotmail.com
Differentiate schema and instance?
Database Instance The term instance is typically used to describe a complete database environment, including the RDBMS software, table structure, stored procedures and other functionality. It is most commonly used when administrators describe multiple instances of the same database.Also Known As: environment Examples: An organization with an employees database might have three different instances: production (used to contain live data), pre-production (used to test new functionality prior to release into production) and development (used by database developers to create new functionality). RELATION SCHEMA A relation schema can be thought of as the basic information describing a table or relation. This includes a set of column names, the data types associated with each column, and the name associated with the entire table. For example, a relation schema for the relation called Students could be expressed using the following representation: Students(sid: string, name: string, login: string, age: integer, gpa: real) There are five fields or columns, with names and types as shown above.
