Friday, February 14, 2020

TFYK: What Is a Relational Schema?

Note: About TYFK posts (Test Your Foundation Knowledge) see the post insert below.
“A relational database stores information in a structured format called a schema. This schema is defined according the rules of database normalization. These rules are meant to ensure the integrity of the data. The schema for a database is broken up into the objects such as tables and constraints. Tables hold your data and are broken down into rows. each row represents a single entity such as a person and has columns which define the attributes of the entity such as age. Constraints define limitations around the data. For example a check constraint might limit the range of valid dates in a datetime column. From there queries can be run to extract data from the database. These queries will often join multiple tables to pull data from them.”
First try to detect the misconceptions, then check against our debunking. If there isn't a match, you can acquire the necessary foundation knowledge in our POSTS, BOOKS, PAPERS, LINKS or, better, organize one of our on-site SEMINARS, which can be customized to specific needs.

Wednesday, February 5, 2020

TYFK: What is a database relationship?

 Note: About TYFK posts (Test Your Foundation Knowledge) see the post insert below.

“Here two or more table are related with each other. This is Database relationship. Database relationship is used a lot. Also known as relational database management system. It is shortly called RDBMS. Here is Join_data table and Interview_data table. For creating a relational database management system both of the table must have a common field. Here Employee_ID is a common field.
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Database relationship types:
01. One-To-One relation
02. One-To-many relation
03. Many-to-many relation.
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01. Minimum one common field is essential in all the tables. The data type of common field and field size will be same in all the tables.
02. There must be a primary key field in any of the table from all the tables.”

First try to detect the misconceptions, then check against our debunking. If there isn't a match, you can acquire the necessary foundation knowledge in our POSTS, BOOKS, PAPERS, LINKS or, better, organize one of our on-site SEMINARS, which can be customized to specific needs.
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