- What is external model?
- What are the different levels of database schema?
- What is the first level of data architecture?
- What are the 3 levels in 3 schema architecture?
- What’s a primary key?
- What is schema architecture?
- What is the 3 tier architecture?
- What are the six basic elements of enterprise architecture?
- What are the levels of architecture?
- What are the three levels of data abstraction with example?
- What cardinality means?
- What is conceptual schema in DBMS?
- What are the main features of a database?
- What is the use of three level architecture?
- What are the 3 types of schema?
- How important is schema markup?
- What are the different types of cardinality?
- What are different data models?
What is external model?
The external model is the end user’s view of the data.
Typically a database is an enterprise system that serves the needs of multiple departments.
At this stage, the conceptual model is independent of both software and hardware.
It does not depend on the DBMS software used to implement the model..
What are the different levels of database schema?
There are mainly three levels of data abstraction: Internal Level: Actual PHYSICAL storage structure and access paths. Conceptual or Logical Level: Structure and constraints for the entire database. External or View level: Describes various user views.
What is the first level of data architecture?
Level 1: Basic Promises Fulfilled – Using a detailed data dictionary and glossary, users develop a basic understanding of the data. The system provides an integrated glossary that can be queried and is tightly integrated with its output; users can easily navigate between data and its definition.
What are the 3 levels in 3 schema architecture?
The ANSI-SPARC database architecture is the basis of most of the modern databases. The three levels present in this architecture are Physical level, Conceptual level and External level.
What’s a primary key?
The PRIMARY KEY constraint uniquely identifies each record in a table. Primary keys must contain UNIQUE values, and cannot contain NULL values. A table can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields).
What is schema architecture?
By Dinesh Thakur. The database schema is a structure or architecture to store data in the database. It creates abstraction(hide the lowest level the detail from the user) between application and physical database.
What is the 3 tier architecture?
Three-tier architecture is a client-server software architecture pattern in which the user interface (presentation), functional process logic (“business rules”), computer data storage and data access are developed and maintained as independent modules, most often on separate platforms.
What are the six basic elements of enterprise architecture?
The six basic elements of an EA documentation method were presented: the EA documentation framework, EA components, current EA views, future EA views, an EA Management and Transition Plan and multi-level threads that include security, standards, and workforce planning.
What are the levels of architecture?
The three architectural levels described by the Zachman Framework, which are also found in the TOGAF and ArchiMate frameworks, represent different degrees of abstraction at which the enterprise can be modeled. In order of increasing detail, these are the Conceptual level, the Logical level, and the Physical level.
What are the three levels of data abstraction with example?
There are mainly 3 levels of data abstraction:Physical: This is the lowest level of data abstraction. … Logical: This level comprises of the information that is actually stored in the database in the form of tables. … View: This is the highest level of abstraction.More items…•
What cardinality means?
Cardinality means two things in databases. … When applied to databases, the meaning is a bit different: it’s the number of distinct values in a table column, relative to the number of rows in the table. Repeated values in the column don’t count. We usually don’t talk about cardinality as a number, though.
What is conceptual schema in DBMS?
A conceptual schema is a high-level description of informational needs underlying the design of a database. … The conceptual model is also known as the data model that can be used to describe the conceptual schema when a database system is implemented.
What are the main features of a database?
It provides several key features:stores data in one central location.allows data to be shared by many users.provides user interfaces to work with the data.creates backups.controls who can access and edit the data.
What is the use of three level architecture?
The three schema architecture is also called ANSI/SPARC architecture or three-level architecture. This framework is used to describe the structure of a specific database system. The three schema architecture is also used to separate the user applications and physical database.
What are the 3 types of schema?
Schema is of three types: Physical schema, logical schema and view schema.
How important is schema markup?
Schema markup is code (semantic vocabulary) that you put on your website to help the search engines return more informative results for users. If you’ve ever used rich snippets, you’ll understand exactly what schema markup is all about. The schema markup told the SERP to display a schedule of upcoming hotel events.
What are the different types of cardinality?
When dealing with columnar value sets, there are three types of cardinality: high-cardinality, normal-cardinality, and low-cardinality. High-cardinality refers to columns with values that are very uncommon or unique. High-cardinality column values are typically identification numbers, email addresses, or user names.
What are different data models?
There are three different types of data models: conceptual, logical and physical, and each has a specific purpose.Conceptual Data Models: High-level, static business structures and concepts.Logical Data Models: Entity types, data attributes and relationships between entities.More items…•