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.
difference between relation sehema and relation instance in dbms
Relation is one record in the database or a tuple. Relationship is that how tables are connected to each other.
Very good question. The different between relation and function is a relation is simply that : any x-value to create y-value while a function, however cannot be defined for multiple values of x
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.
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.
difference between relation sehema and relation instance in dbms
The terms instance and database are closely related, but don't refer to the same thing. The database is the set of files where application data (the reason for a database) and meta data is stored. An instance is the software (and memory) that Oracle uses to manipulate the data in the database. In order for the instance to be able to manipulate that data, the instance must open the database. A database can be opened (or mounted) by more than one instance, however, an instance can open at most one database.
Relation is one record in the database or a tuple. Relationship is that how tables are connected to each other.
A relation is an assciation between two or more entities.
Relation: In Database a relation represents a table or an entity that contain diffrenet attributes.An Entity constructs a relation(table) in DBMS . Relationship: In Data base relationship is that how the two entities are connected to each other ,i.e what kind of relationship type they hold between them.Primary/Foreign key is used to specify or hold this relationship. By Tanzeel Ur Rahman Bhatti
the difference is about the transactions. the normal database is not included deadline, but the real time database is.
Database is the data stored in the server and Database administrator is the person who designs the database.
Difference?? There is no relation.
In general, a database is a collection of related data. In more specific terms, a database is typically a collection of computer files, usually stored on disk, used to contain and manage this data. The logical structure of a database (as organized in tables, indexes, views, etc.) does not necessarily correspond directly to its physical structure (the data files, transaction log files, etc.). A database instance is the instantiation of memory structures and processes by a database management system manages the logical and physical structures and the data organized and stored therein. An application program must connect to and interact with the database instance in order to insert, retrieve, modify, and/or delete data stored in the database.
CACHE is multidimensional and postconsonantal database and its supporting scripting
differences between document management and database technology
DBMS: Set of software applications combined w/ a database