What is a database schema?
A database schema represents the logical configuration of all or part of a relational database.
It can exist both as a visual representation and as a set of formulas known as integrity constraints that govern a database. These formulas are expressed in a data definition language, such as SQL. As part of a data dictionary, a database schema indicates how the entities that make up the database relate to one another, including tables, views, stored procedures, and more.
Typically, a database designer creates a database schema to help programmers whose software will interact with the database. The process of creating a database schema is called data modeling. When following the three-schema approach to database design, this step would follow the creation of a conceptual schema. Conceptual schemas focus on an organization’s informational needs rather than the structure of a database.
There are two main kinds of database schema:
- A logical database schema conveys the logical constraints that apply to the stored data. It may define integrity constraints, views, and tables.
- A physical database schema lays out how data is stored physically on a storage system in terms of files and indices.
At the most basic level, a database schema indicates which tables or relations make up the database, as well as the fields included on each table. Thus, the terms schema diagram and entity-relationship diagram are often interchangeable.
What is schema?
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.
Some other database products draw a distinction. For example, in the Oracle Database product, a schema represents only a part of a database: the tables and other objects owned by a single user.
What is a Data Model?
A data model is an abstract model, that documents and organizes the enterprise data for communication between developers. Most of the times a data model is represented in a diagram. A data model is used as a plan for developing software, specifically how data is stored and accessed. A data model of your database can support the analysis, design, documentation and migration of underlying database structures.
How to design database/schema?
In software engineering, data modeling is the process of creating a data model for an information system. This is done by applying formal data modeling techniques.
SQLDBM offers you an easy, convenient way to design your database absolutely anywhere on any browser, working away without need for any extra database engine or database modelling tools or apps. Use SQLDBM to design and manage both large and small databases and data models on the fly. All while incorporating any needed database rules and objects such as database keys, schemas, indexes, column constraints and relationships.
SQLDBM helps you:
- Create database objects like tables, objects, relationships, indexes, quickly and intuitively
- Alter and edit database objects inline in your diagram
- Copy or Move columns across tables
- Zoom in and out of diagrams
- On-the- spot design anywhere on any browser
For more information you can check our post about Main Features.