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In database design a RELATION is the relationship that you build between two or more tables.
As an example lets say you have a Customer table. In this table you have lots of fields
FirstName, LastName, Address, City, State, PostalCode, StatusID; etc.......
Now StatusID is going to be a numeric value. Lets say that the value is 1
Now you will have a Status Table with multiple fields (ex)
StatusID, StatusName, Active, etc.....
Now when you display customer information you will not want to show a StatusID as nobody will know what this is. You will want to show the NAME associated with the status. To do this you will create a releationship between StatusID in the Customer table and StatusID in the Status table. In doing so you will provide for faster lookup results, a constraint that does not permit a numeric value in the StatusID field in the customer table that is NOT in the StatusID field of the Status table.
THEN... To show correct Results you would write a query something like:
SELECT FirstName, LastName, Address, City, State, PostalCode, StatusName
FROM Customers as c
JOIN Status as s on s.StatusID = c.StatusID
A relational Schema is simply a representation of your database highlighting the relationships that you have created throughout.
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What is the Difference between relation schema and relation instance?
difference between relation sehema and relation instance in dbms
How do you convert an ER diagram into a Relational Schema?
secret...know it yourself
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 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 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 schema and relation instance?
difference between relation sehema and relation instance in dbms
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.
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 do you mean about schema in RDBMS?
In a relational database, the schema defines the tables, the fields in each table, and the relationships between fields and tables.
What is relational schema?
A relational schema is a structure that represents the logical view or design of a database. It defines how the data is organized and the relationships between different entities or tables. It typically includes the names of the tables, their attributes or columns, and the constraints that define the relationships between them.
How do you convert an ER diagram into a Relational Schema?
secret...know it yourself
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.
In a relational schema each tuple is divided into fields called?
In a relational schema, each tuple is divided into fields called attributes. Each attribute corresponds to a specific piece of data within the tuple.
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.
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
Why 4NF is preferable then bcnf .with example?
Normalization is a process to reduce the redundancy by removing function dependencies BCNF (Boyece code normal form) has all functional dependencies A to B are trivial of discriminator should be superkey. To get relation in BCNF, Splitting the relation schema not neccessarily preserve all functional dependency, Loss less decomposition and dependency are main points for the normalization sometime, it is not possible to get a BCNF decomposition that is dependency, preserving. While 4NF has very similar definition as BCNF. A relational Schema is in 4NF, if all multivalued dependencies A to B are trivial and determinate A is superkey of schema. If a relational schema is in 4nf, it is already in BCNF. and 4NF decomposition preserve the all functional dependency. so 4NF is preferable than to have BCNF.
What is Schema in the term of Database Management System?
Schema means structure of the databse. Like, tables, constraints, relation
