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.
Characteristic of a good database is: We should be able to store all kinds of data that exist in this real world. Data and applications should be isolated. Because the database is a system that gives the platform to store the data, and the data is the one that allows the database to work.
The Elements of a Database
- The database schema.
- Schema objects.
- Indexes.
- Tables.
- Fields and columns.
- Records and rows.
- Keys.
- Relationships.
The main difference between logical database design and physical database design is that logical database design helps to define the data elements and their relationships, but physical database design helps to design the actual database based on the requirements gathered during the logical data design.
Database design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model. This theoretical representation of the data is called an ontology.
DBMS itself is one of the features of database language which is a software application for management of data. Database language also facilitates modification and alteration of query results by averaging, counting, summing, etc. Database language enables user's interaction with other applications.
1) Front- end interface : It is the link between the user and the database oriented software, through which the user communicates to the back-end database. 2) Back-end Database : It stores data which can be retrieved by the user only to the extent he is authorised to access.
The design process
- Determine the purpose of your database. This helps prepare you for the remaining steps.
- Find and organize the information required.
- Divide the information into tables.
- Turn information items into columns.
- Specify primary keys.
- Set up the table relationships.
- Refine your design.
- Apply the normalization rules.
Tables are database objects that contain all the data in a database. In tables, data is logically organized in a row-and-column format similar to a spreadsheet. Each row represents a unique record, and each column represents a field in the record.
Data consistency is ensured in a database because there is no data redundancy. All data appears consistently across the database and the data is same for all the users viewing the database. Moreover, any changes made to the database are immediately reflected to all the users and there is no data inconsistency.
The document describes, how the database that will support the [Application] Data Model with details of the logical and physical definitions. The document provides the functional and non-functional usage of the tables, considerations and requirements.
Some of the most used database software include MySQL, Microsoft SQL Server, Microsoft Access DBMS, Oracle, IBM DB2, and FoxPro. The database software list mentioned above covers the popular DBMS available.
A database is typically designed so that it is easy to store and access information. A good database is crucial to any company or organisation. This is because the database stores all the pertinent details about the company such as employee records, transactional records, salary details etc.
A logical database must be able to access and identify all files within the storage system to operate correctly, whereas a physical database manages a much smaller field of information. Sometimes, a physical database stores only a single file with one value or word in it.
A database is an organized collection of structured information, or data, typically stored electronically in a computer system. The data can then be easily accessed, managed, modified, updated, controlled, and organized. Most databases use structured query language (SQL) for writing and querying data.
When choosing a DBMS from the variety of concepts and vendors, you should consider the following points before making a decision.
- Data Model.
- Data Consistency.
- Data Security.
- Data Protection.
- Multi Access and Integration.
- Efficiency.
- Usability.
- Implementation and Service Costs.
The database designer is responsible for defining the detailed database design, including tables, indexes, views, constraints, triggers, stored procedures, and other database-specific constructs needed to store, retrieve, and delete persistent objects.
Data is usually accessed with queries or business intelligence (BI) tools. It's important for any database to rapidly respond with deduped data. The ability to support a broad variety of data so that it can be aggregated, analyzed, and reports generated.
An entity relationship diagram (ERD), also known as an entity relationship model, is a graphical representation that depicts relationships among people, objects, places, concepts or events within an information technology (IT) system.
Effective database planning means that your software is capable of managing and consolidating all the data generated and relied upon by your business. A good database plan will allow your organisation to develop a clear structure for the way in which data is stored and managed by every person or application using it.
Data tables display information in a grid-like format of rows and columns. They organize information in a way that's easy to scan so that users can look for patterns and develop insights from data. Data tables can contain: Interactive components (such as chips, buttons, or menus)
Data modeling is the process of creating a visual representation of either a whole information system or parts of it to communicate connections between data points and structures. The process begins by collecting information about business requirements from stakeholders and end users.
Why use NoSQL?
- Support large numbers of concurrent users (tens of thousands, perhaps millions)
- Deliver highly responsive experiences to a globally distributed base of users.
- Be always available – no downtime.
- Handle semi- and unstructured data.
- Rapidly adapt to changing requirements with frequent updates and new features.
Explain the factors influencing physical database design
- Factors influencing physical database design. Let us see the important factors that influence physical database design −
- Transactions and queries.
- Frequency Analysis.
- Time constraints.
- Update frequency.
- Uniqueness constraints.
DBMS TutorialsThe methodology is depicted as a bit by bit guide to the three main phases of database design, namely: conceptual, logical, and physical design.
Types of database models
Relational model. Network model. Object-oriented database model.Database design is a collection of steps that help create, implement, and maintain a business's data management systems. The primary purpose of designing a database is to produce physical and logical models of designs for the proposed database system.
A badly designed database has the following problems: Related data is scattered over various tables. A change must be updated at many places. It's possible that the information is only half present, it's there in one table, but missing in another one. Data is inconsistent or ambiguous (poly interpretable).
Create a database without using a template
- On the File tab, click New, and then click Blank Database.
- Type a file name in the File Name box.
- Click Create.
- Begin typing to add data, or you can paste data from another source, as described in the section Copy data from another source into an Access table.
Definition. Logical database design is the process of transforming (or mapping) a conceptual schema of the application domain into a schema for the data model underlying a particular DBMS, such as the relational or object-oriented data model.
The basic building blocks of all data models are entities, attributes, and relationships. An entity is anything, such as a person, place, thing, or event, about which data are to be collected and stored. Entities may be physical objects such as customers or products.
Review of super key and primary keyRemember that a super key is any set of attributes whose values, taken together, uniquely identify each row of a table—and that a primary key is the specific super key set of attributes that we picked to serve as the unique identifier for rows of this table.
There are 4 key steps to design the best Database Schema:
- Establishing the Requirements.
- Selecting a Simple Primary Key.
- Defining Entity Relationships.
- Enhancing Designs for Specific Features.
