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tablespace,segment,extent,oracle blocks.. are the logical schema of a database
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Is schema a logical structure or physical structure in oracle database?
the schema can be termed either conceptual or logical or physical. But mostly speaking, the term schema is used to refer to a logical structure.
What is a database schema?
A database schema is described in a formal language supported by the database management system (DBMS). In a relational database, the schema defines the tables, the fields in each table, and the relationships between fields and tables. Schemas are generally stored in a data dictionary. Although a schema is defined in text database language, the term is often used to refer to a graphical depiction of the database structure Levels of database schema 1. Conceptual schema, a map of concepts and their relationships 2. Logical schema, a map of entities and their attributes and relations 3. Physical schema, a particular implementation of a logical schema 4. Schema object, Oracle database object 5. Schema is the over all structure of the database
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 Schema and instances?
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 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 do you mean by Schema in DBMS?
overall design of the database
What is schema object of database?
We know that schema in the database is refer to the basic design of that database and is stored in an object . That object is known as schema object of database.
What is the difference between schema and database?
Database schema are the logical structure of entities (tables or object classes) and their relationships (keys, or object associations) in a database. Schema can exist at different levels of abstraction (see: en.wikipedia.org/wiki/Database_schema). Schema themselves may or may not exist as such in a database. In general schema at the higher levels of abstraction are design models that are captured in printed documents, and authored by business analysts and database designers, rather than created by database programmers and stored in the database itself. But in some types of databases, schema at any level of abstaction can be realized physically. In Oracle databases, schema can be realized as schema objects, which are a part of an Oracle database. These schema objects may represent a human user's conceptual model of the knowledge captured in an enterprise database. Thus defined, there can be many schema that can be associated with one physical database. In other kinds of relational database, an abstract user's schema can be represented by logically linked metadata, views, and stored procedures assocated with a user class. In object-oriented databases, especially those based on the highly self-referential language Smalltalk (e.g. Gemstone/S), schema are realized as "physical" objects in the database as a matter of course, as well as in the logical models captured in design documents. The schema objects in such databases are, in essence, the classes comprising the infrastructure of the database or application. Oracle-style user schema are readily created; these would be realized as user interface orchestrator classes.
What is logical data independence and its importance?
Logical data independence refers to the ability to make changes to the logical structure of the database without affecting the application programs that access that data. This is important because it allows for easier maintenance and updates to the database system, as changes to the database schema can be made without disrupting the application layer.
What are the Types of database schema architecture?
The Star & Snowflake are two common type of database Schema.
What is the explanation for the components of database systems?
A Database consists of the following components.Schema - A Schema is a logical grouping of a set of database tablesTable - A table is a logical sub unit of information that is split up into rows and columns - much like the MS XL spreadsheetAll the data that is stored in a database is organized into tables and schemas.Apart from this, a database can have:ViewsFunctionsStored Proceduresetc
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.
