What is the difference between ERD and relational schema?
What is the difference between ERD and relational schema?
In short, an ERD is an abstract concept of our database, it speaks in entities and attributes, an entity model. A relational model defines formats and relations in a way a database could understand, a data model. ERD is belongs to relationship between entities, it is different from relation model.
What is database modeling how is ER model different from other data models?
AGE
| S.No. | ER model |
|---|---|
| 1. | ER model is the high level or conceptual model. |
| 2. | It is used by people who don’t know how database is implemented. |
| 3. | It represents collection of entities and describes relationship between them. |
What is database schema diagram?
A schema diagram is a diagram which contains entities and the attributes that will define that schema. A schema diagram only shows us the database design. It does not show the actual data of the database. Schema can be a single table or it can have more than one table which is related.
What is the difference between ER modeling and dimensional modeling?
The ER modeling is for databases that are OLTP databases which uses normalized data using 1st or 2nd or 3rd normal forms. Dimensional Modeling is used in data warehouses that uses 3rd normal form. It contains denormalized data.
What is the difference between ER and EER diagram?
EER diagram is an enhanced ER diagram. ER diagram is a visual representation of data based on ER model, and it describes how entities are related to each other in the database. EER diagram is a visual representation of data, based on EER model that is an extension of the original entity-relationship (ER) model.
What is the difference between schema and database?
A database is the main container, it contains the data and log files, and all the schemas within it. You always back up a database, it is a discrete unit on its own. Schemas are like folders within a database, and are mainly used to group logical objects together, which leads to ease of setting permissions by schema.
What is data warehouse schema?
Schema is a logical description of the entire database. It includes the name and description of records of all record types including all associated data-items and aggregates. Much like a database, a data warehouse also requires to maintain a schema.