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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
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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 are the Types of database schema architecture?
The Star & Snowflake are two common type of database Schema.
How does one read a database schema?
One can easily read a database schema through any software available currently. Simpy because a database schema is a blueprint which can be read by a software.
What do you mean by logical schema in database?
tablespace,segment,extent,oracle blocks.. are the logical schema of a database
What are database schema and sub-schemas?
A database schema is an actual plan for a database system. Sub-schemas are separate divisions that are used to achieve the plan for the database system.
How is data organized in a database?
In the manner described in the database schema.
What language Enables a database administrator to define schema components?
Schema DDL
Difference between database schema and a database state in dbms?
The distinction between database schema and database state is very important. When we define a new database, we specify its database schema only to the DBMS. At this point, the corresponding database state is the empty state with no data. We get the initial state of the database when the database is first populated or loaded with the initial data. From then on, every time an update operation is applied to the database, we get another database state. At any point in time, the database has a current state. The DBMS is partly responsible for ensuring that every state of the database is a valid state-that is, a state that satisfies the structure and constraints specified in the schema. The DBMS stores the descriptions of the schema constructs and constraints-also called the meta-data-in the DBMS catalog so that DBMS software can refer to the schema whenever it needs to. The schema is sometimes called the intension, and a database state an extension of the schema.
Data base state vs database schema?
The database schema is the description of the database. It defines how the database is set up and what data it is to contain and control. This description is given to the DBMS to manage the data. The database state is an image of how the database looks at any given time. The database schema is set unless you change how the database is structured. The database state will change whenever new data is entered into the database and the database is updated.
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 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 are predicates that define correct database states and relationship with in database?
schema
