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Difference between schema sub schema and instance in DBMS in detail?
Wiki User
∙ 12y ago
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
Wiki User
∙ 12y ago
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What is the Difference between relation schema and relation instance?
difference between relation sehema and relation instance in dbms
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 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.
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
What is data structure in a detail?
Whatever is needed for the task and planed/designed in the database schema.
Difference between user and schema for DB2?
In DB2, a user is an individual who is granted permissions to access and interact with the database, while a schema is a named collection of tables, views, procedures, and other database objects owned by a user. Users are associated with schemas to define their default schema for objects they create.
Difference between catalog and schema?
A catalog is a set of tables which contains the definitions or descriptions of the database structure and its constraints. For example it could store the structure of each file +Type and Format of each data item stored in the file. A catalog is a type of schema and a schema is what defines a data elements and their interrelationships.
What is schema instance?
In DBMS,Schema is the overall Design of the Database.Instance is the information stored in the Database at a particular moment.In programming,you declare a variable which corresponds to "Schema".But its values changes as and when required which corresponds to "Instance". Google about levels of Database Abstraction. Physical Schema describes database design at physical level while a logical schema describes the database design at the logical level.A database may also have several schemas at the view level, sometimes called subschemas, that describe different views of the database.
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 schema and background knowledge?
I think background knowledge is something you can build with a student, whereas schema is what they already have experienced. I'm studying this stuff in grad school, and I googled this trying to find an answer. I'm pretty certain that's essentially the difference. and also teacher can not provide students with schemata but can provide students with background knowledge.
