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- First Normal Form (1NF): :-> This is the most basic level of
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normalization. In 1NF, each table cell should contain _only a single value, and each column should have a unique name_. The first normal form helps to eliminate duplicate data and simplify queries.
- Second Normal Form (2NF): :-> 2NF eliminates redundant data by requiring that each _non-key attribute_ be dependent on the primary key. This means that _each column should be directly related to the primary key_, and not to other
- Second Normal Form (2NF): :-> 2NF eliminates redundant data by requiring that each _non-key attribute_ be ==dependent on the primary key==. This means that _each column should be directly related to the primary key_, and not to other
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columns.
- Third Normal Form (3NF): :-> 3NF builds on 2NF by requiring
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- Fourth Normal Form (4NF): 4NF is a further refinement of BCNF that ensures that _a table does not contain any multi-valued dependencies._
- Fifth Normal Form (5NF): 5NF is the highest level of normalization and involves decomposing a table into smaller tables to _remove data redundancy and improve data integrity._
- Anomaly
- Update Anomalies
- Update Anomalies #flashcard
- Insertion anomalies
- If there is a new row inserted in the table and it creates the
inconsistency in the table then it is called the insertion anomaly. For
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it is not allocated to any department then we cannot insert it in the
table so, it will create an insertion anomaly.
- Deletion anomalies
- If we delete some rows from the table and if any other information or
data which is required is also deleted from the database, this is called
the deletion anomaly in the database. For example, in the above table,
if we want to delete the department number ECT669 then the details of
Rajesh will also be deleted since Rajesh's details are dependent on the
row of ECT669. So, there will be deletion anomalies in the table.
- Modification anomalies
- When we update some rows in the table, and if it leads to the
inconsistency of the table then this anomaly occurs. This type of
anomaly is known as an updation anomaly. In the above table, if we want
to update the address of Ramesh then we will have to update all the rows
where Ramesh is present. If during the update we miss any single row,
then there will be two addresses of Ramesh, which will lead to
inconsistent and wrong databases.
- LATER Block 4
- DONE Distributed DBMS
- DONE client server arch #flashcard