Keys in databases help uniquely identify rows in tables. The main types of keys are:
1. Primary keys uniquely identify each row and cannot contain duplicate values.
2. Foreign keys link rows between tables and must match the primary key of another table.
3. Composite/compound keys combine two or more columns to uniquely identify rows, since the columns individually may not be unique.
Surrogate keys are artificial primary keys used when the table lacks a natural candidate key to uniquely identify rows. Other keys include unique keys, alternate keys, candidate keys, and super keys. Keys are important for maintaining data integrity and relationships between tables.
The following presentation represents database keys and its types, and also database relationship and its types with references. It will help you to know about what is keys and database relationship.
Relational database intro for marketersSteve Finlay
If you work in marketing and product management, you depend heavily on relational databases, even if you are not aware of them. This short presentation explains the most important things you need to know about why they are necessary, and how they work.
Data Warehousing and Business Intelligence is one of the hottest skills today, and is the cornerstone for reporting, data science, and analytics. This course teaches the fundamentals with examples plus a project to fully illustrate the concepts.
The following presentation represents database keys and its types, and also database relationship and its types with references. It will help you to know about what is keys and database relationship.
Relational database intro for marketersSteve Finlay
If you work in marketing and product management, you depend heavily on relational databases, even if you are not aware of them. This short presentation explains the most important things you need to know about why they are necessary, and how they work.
Data Warehousing and Business Intelligence is one of the hottest skills today, and is the cornerstone for reporting, data science, and analytics. This course teaches the fundamentals with examples plus a project to fully illustrate the concepts.
it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU .it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU .it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU
### Introduction
The Entity-Relationship Model (ERM) serves as a crucial concept in the realm of database design, offering a conceptual and visual framework for organizing and structuring data within a database system. Developed by Peter Chen in 1976, this model has evolved into a fundamental tool widely employed in both academic and industrial database design.
### Core Elements: Entities and Attributes
At its essence, the ERM revolves around entities, which can be real-world objects like a person or a car, or abstract concepts such as an order or a transaction. Each entity is characterized by its attributes—properties defining the entity and specifying the type of information storable about it.
### Relationship Dynamics
Entities in the ERM are not isolated; they are interconnected through relationships, representing associations and interactions between them. These relationships are pivotal in defining the connections and dependencies between different entities within a database. They can take the form of one-to-one, one-to-many, or many-to-many, mirroring the intricate web of real-world interactions.
### Visual Representation
Graphical notations play a crucial role in ERM, employing symbols like rectangles for entities, ovals for attributes, and diamond shapes for relationships. Lines connect these symbols, creating a visual representation that simplifies comprehension for designers, developers, and stakeholders.
### Strengths of ERM
One standout feature of the ERM is its capability to model complex relationships and business rules in a straightforward and understandable manner. This simplification streamlines the database design process, allowing designers to concentrate on the logical structure of data without delving into intricate technical details. Furthermore, the model facilitates effective communication among stakeholders, ensuring a shared understanding of the data model.
### Versatility and Adaptability
ERM isn't confined to just database design—it plays a vital role in documenting existing databases and acts as a blueprint for their implementation and maintenance. As databases evolve, the ERM can be updated to accommodate changes in data structure and relationships. This adaptability makes it a valuable tool across diverse applications, including business, finance, healthcare, and education.
### Normalization and Efficiency
Normalization, closely associated with the ERM, is a process that minimizes redundancy and dependency in a database. By adhering to normalization principles, designers can create databases that are efficient, scalable, and easy to maintain. This involves breaking down complex data structures into simpler, more manageable forms, reducing the risk of data anomalies and inconsistencies.
### Limitations and Considerations
While widely used and effective, the ERM does have its limitations. It primarily focuses on the logical representation of data and may not fully capture certain aspects of a system's.
it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU .it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU .it is a ppt for reference for KEYS IN DBMS YOU CAN USE IT FOR PREPARING FOR YOUR MTE AND ETE EXAMS . YOU CAN DOWNLOAD IT , IT IS EASY TO UNDERSTAND AND CAN HELP YOU A LOT IN YOUR COLLEDGE EXAMS .AS THE CONTENT IS IN VERY SHORT AND CAN BE VERY USEFUL FOR YOU
### Introduction
The Entity-Relationship Model (ERM) serves as a crucial concept in the realm of database design, offering a conceptual and visual framework for organizing and structuring data within a database system. Developed by Peter Chen in 1976, this model has evolved into a fundamental tool widely employed in both academic and industrial database design.
### Core Elements: Entities and Attributes
At its essence, the ERM revolves around entities, which can be real-world objects like a person or a car, or abstract concepts such as an order or a transaction. Each entity is characterized by its attributes—properties defining the entity and specifying the type of information storable about it.
### Relationship Dynamics
Entities in the ERM are not isolated; they are interconnected through relationships, representing associations and interactions between them. These relationships are pivotal in defining the connections and dependencies between different entities within a database. They can take the form of one-to-one, one-to-many, or many-to-many, mirroring the intricate web of real-world interactions.
### Visual Representation
Graphical notations play a crucial role in ERM, employing symbols like rectangles for entities, ovals for attributes, and diamond shapes for relationships. Lines connect these symbols, creating a visual representation that simplifies comprehension for designers, developers, and stakeholders.
### Strengths of ERM
One standout feature of the ERM is its capability to model complex relationships and business rules in a straightforward and understandable manner. This simplification streamlines the database design process, allowing designers to concentrate on the logical structure of data without delving into intricate technical details. Furthermore, the model facilitates effective communication among stakeholders, ensuring a shared understanding of the data model.
### Versatility and Adaptability
ERM isn't confined to just database design—it plays a vital role in documenting existing databases and acts as a blueprint for their implementation and maintenance. As databases evolve, the ERM can be updated to accommodate changes in data structure and relationships. This adaptability makes it a valuable tool across diverse applications, including business, finance, healthcare, and education.
### Normalization and Efficiency
Normalization, closely associated with the ERM, is a process that minimizes redundancy and dependency in a database. By adhering to normalization principles, designers can create databases that are efficient, scalable, and easy to maintain. This involves breaking down complex data structures into simpler, more manageable forms, reducing the risk of data anomalies and inconsistencies.
### Limitations and Considerations
While widely used and effective, the ERM does have its limitations. It primarily focuses on the logical representation of data and may not fully capture certain aspects of a system's.
A Key is an attribute or a set of attributes in a relation that identifies a tuple (record) in a relation. The keys are defined in a table to access or sequence the stored data quickly and smoothly. They are also used to create relationship between different tables.
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Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
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Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
3. Key
“KEYS in DBMS is an attribute or set of
attributes which helps you to identify a
row(tuple) in a relation(table)”
4. Why we need a Key?
1. Keys help us to identify any row of data in a table.
In a real-world application, a table could contain
thousands of records.
Moreover, the records could be duplicated.
Keys ensure that you can uniquely identify a
table record despite these challenges.
5. Why we need a Key?
2. Allows you to establish a relationship
between and identify the relation between
tables
3. Help you to enforce identity and
integrity in the relationship.
6. Types of Keys
1. Super Key
2. Primary Key
3. Unique Key
4. Candidate Key
5. Alternate Key
There are mainly different types of Keys
6. Foreign Key
7. Compound Key
8. Composite Key
9. Surrogate Key
7. Super key
A super key is a group of single or multiple keys which
identifies rows in a table. A Super key may have additional
attributes that are not needed for unique identification.
In the above-given example, EmpSSN and EmpNum name are superkeys.
8. EID Name Mobile No AC
1 Komal
Sharma
9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
Super Key
9. PRIMARY KEY
PRIMARY KEY is a column or group of columns in a table
that uniquely identify every row in that table. The Primary
Key can't be a duplicate meaning the same value can't appear
more than once in the table. A table cannot have more than
one primary key.
10. Rules for defining Primary key
1. Two rows can't have the same primary key value
2. It must for every row to have a primary key value.
3. The primary key field cannot be null.
4. The value in a primary key column can never be
modified or updated if any foreign key refers to that
primary key.
11. EID Name Mobile No AC
1 Komal Sharma 9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
Primary Key
In the following example, EID is a Primary Key.
12. Unique KEY
Unique KEY is a column or group of columns in a table that
uniquely identify every row in that table. The Unique Key
can't be a duplicate meaning the same value can't appear
more than once in the table. A table can have more than one
Unique key.
13. Rules for defining Unique key
1. Two rows can have the same Unique key value
2. The Unique key field can be null.
14. EID Name Mobile No AC
1 Komal Sharma 9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
Unique Key
In the following example, EID and ACis a Unique Key.
15. ALTERNATE KEYS
ALTERNATE KEYS is a column or group of columns in a
table that uniquely identify every row in that table. A table can
have multiple choices for a primary key but only one can be set
as the primary key.
All the keys which are not primary key are called an Alternate
Key.
16. Example:
In this table, StudID, Roll No, Email are qualified to
become a primary key. But since StudID is the primary key,
Roll No, Email becomes the alternative key.
17. EID Name Mobile No AC
1 Komal Sharma 9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
Alternate Key
18. CANDIDATE KEY
CANDIDATE KEY is a set of attributes that uniquely
identify tuples in a table. Candidate Key is a super key with
no repeated attributes. The Primary key should be selected
from the candidate keys. Every table must have at least a
single candidate key. A table can have multiple candidate keys
but only a single primary key.
19. Properties of Candidate key
1. It must contain unique values
2. Candidate key may have multiple attributes
3. Must not contain null values
4. It should contain minimum fields to ensure uniqueness
5. Uniquely identify each record in a table
20. EID Name Mobile
No
AC
1 Komal
Sharma
9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
Candidate Key
21.
22. FOREIGN KEY
FOREIGN KEY is a column that creates a relationship
between two tables.
The purpose of Foreign keys is to maintain data integrity and
allow navigation between two different instances of an
entity. It acts as a cross-reference between two tables as it
references the primary key of another table.
23. EID Name Mobile No AC
1 Komal
Sharma
9876543210 12
2 Rahul 8789654896 34
3 Prince
Gupta
9854756985 56
4 Shalu
Gupta
5896325878 78
5 Ritik Joshi 7896547896 19
AC Salary Driving
License
12 5000 DL12345
6
34 4500 DL12378
6
75 1850 DL12398
7
78 5520 DL12325
8
20 4896 DL12314
7
Foreign Key
Primary Key
Alternate Key
24. COMPOUND KEY
COMPOUND KEY has two or more attributes that allow you to
uniquely recognize a specific record. It is possible that each column
may not be unique by itself within the database.
However, when combined with the other column or columns the
combination of composite keys become unique. The purpose of the
compound key in database is to uniquely identify each record in the
table.
25. EID Name Mobile No AC
1 Komal Sharma 9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
Compound Key
In this example, Mobile No can't be a primary key as it does not uniquely identify
a record. However, a compound key of Mobile No could be used as it
uniquely identified each record.
26. COMPOSITE KEY
COMPOSITE KEY is a combination of two or
more columns that uniquely identify rows in a table.
The combination of columns guarantees uniqueness,
though individually uniqueness is not guaranteed.
Hence, they are combined to uniquely identify
records in a table.
27. EID Name Mobile No AC
1 Komal Sharma 9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
COMPOSITE Key
28. SURROGATE KEYS
SURROGATE KEYs is An artificial key which aims to uniquely
identify each record is called a surrogate key.
This kind of partial key in dbms is unique because it is created
when you don't have any natural primary key. They do not lend
any meaning to the data in the table.
Surrogate key is usually an integer.
29. Example, shown shift timings of the different employee. In
this example, a surrogate key is needed to uniquely
identify each employee.
Surrogate keys in sql are allowed when No property has
the parameter of the primary key.
30. EID Name Mobile
No
AC
1 Komal Sharma 9876543210 12
2 Rahul 8789654896 34
3 Prince Gupta 9854756985 56
4 Shalu Gupta 5896325878 78
5 Ritik Joshi 7896547896 19
AC Salary Driving
License
12 5000 DL123456
34 4500 DL123786
75 1850 DL123987
78 5520 DL123258
20 4896 DL123147
Foreign
Key
Primary Key
Primary Key
Super Key
Candidate Key
Alternate Key
Compound Key