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[Music]
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thank you
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[Music]
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Hello friends welcome back to our
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channel so in today's session we'll
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discuss about one more Topic in dbms
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that is anomalies
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so first let us discuss about what is
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anomaly and what are the different types
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of anomalies and this anomaly is a fault
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all right
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occurs
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in a database
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right so
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which
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is because of poor design poor design of
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database
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or storing the data right
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this is called an anomaly so that means
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it's some fault occur in the database so
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what actually these Faults Are what
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actually these anomalies so there are
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three categories of anomalies one is
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insertion anomaly
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insertion anomaly
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the second one deletion anomaly
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and the third one updation anomaly
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so this insertion anomaly will be
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occurred during the insertion of a data
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into the database so this occurs
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during insert inserting data
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inserting
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data
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and this anomaly occurs
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during
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deletion of data
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and this occurs
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during
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updating the data
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that means the faults or errors we get
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during insertion is called the insertion
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anomaly and
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the fault occurs during the deletion of
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data so if you want to delete some data
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so the possible faults we may get is a
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deletion anomaly and this updating the
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data
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is comes under the updating anomaly
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right
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so now we'll go with the insertion
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anomaly so let me discuss about uh
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theoretically after that I will show you
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an example right so I will take one
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table and I will show you what is the
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insertion anomaly and what is the
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deletion anomaly when it will be occurs
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and I will I will say all these things
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after the after this explanation so in
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such an anomaly
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so while inserting the data
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if you are unable to insert
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without presence of other attributes
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reviews that means we know that a table
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consists of attributes so if we are
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unable to insert a data for a particular
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attribute without the presence of other
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attribute that means a dependency so one
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attribute is dependent on another so
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without giving the value of one
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attribute if the table doesn't take the
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value of other attribute then we call it
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as a insertion anomaly so I'll give you
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the example okay so deletion
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if some data is deleted
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with the duration of other data
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with the deletion of other data that
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means
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if you are supposed to delete some data
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in the table which may delete another
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attributes that type of anomaly we call
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it is a deletion anomaly right so if the
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index list if you want to delete a one
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attribute so which may delete the some
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other values some other values okay some
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other information so that type of
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anomaly is a relational number and
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update anomaly
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update anomaly so if our
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table consists of redundancy
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if our table consists of redundancy then
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automatically this updation anomaly will
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be occurred that means if you want to
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update one attribute or one row so it
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should be reflected on another rows also
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because of redundancy
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right so that type of anomaly we call it
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as an updation anomaly so these are the
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different types of anomalies available
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in dbms and only one way to avoid this
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anomalies is by going with the
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normalization
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normalization or we can simply call it
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as a decomposition
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decomposition that is also a lossless
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decomposition loss less decomposition
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decomposition means dividing the table
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into different tables sub tables and
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also splitting and joining both we can
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call it as an organization
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right so here because of these anomalies
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we are going to split the tables
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and we need to uh give a relation and
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maybe between tables okay relationship
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between different tables
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so these anomalies because of these
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anomalies to avoid these anomalies we
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are moving with the normalization or
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decomposition this is the only solution
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to avoid the anomalies okay insertion
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deletion and updation and obvious now ah
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let me take one table and I will explain
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you about the in insertion anomaly so
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that means inserting the data
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we can't intercept the data without the
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presence of other attributes and
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deletion deleting some data which may
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lead to delete of some other information
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and updation because of Red Energy so
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we'll see all these three anomalies by
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taking one example one table and then I
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will explain you about this insertion
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deletion and updation but anomalies are
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nothing but a faults occur in a database
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because of poor design or storing data
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in
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flat database
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fly database
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right so let us take one example
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so let us take this example so this is a
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details of a student who enrolls the
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course okay so let us take so this is a
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enrollment of course other than their
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academics okay so the students May
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enroll or may not enroll so here the
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primary key
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here the primary key
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is a combination of the student ID
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plus course title
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course title because one student may
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enrolled in multiple courses so we can't
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consider the student ID as a primary key
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right primary key means unique so that
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should not be redundancy but here uh we
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can't take the student ID as a primary
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key because one student may enroll
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different courses similarly one course
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can be enrolled by different students so
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we can't make this course title also as
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a primary key so but we can give both
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student ID and the course title as a
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primary key right so here it is a
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primary key now coming to the insertion
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anomaly
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insertion anomaly
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so what is this insertion anomaly so we
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can't able to insert the data without
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the presence of other data so here if in
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this particular table you can see
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so if eggs new newly joined student okay
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we can't add the newly joined student
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until he or she enrolled to the course
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title
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okay so without the course title we
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can't insert the student details here
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because course title is also a part of a
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primary key it should not be kept null
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so such a type of anomaly we call it as
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a insertion anomaly so here so
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so data
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can't be inserted
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foreign
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right so such type of anomaly we call it
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as a insertion anomaly insertion and
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only
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right so next deletion
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deletion so if you consider
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so after some days just the students are
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they have left the college so I need to
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remove this
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uh student details right so if you
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delete this student details
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so if you delete the student details
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automatically the course which was
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enrolled by this particular student will
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also be deleted and the course is only
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enrolled with this particular student
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itself only with one student
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so automatically this course details
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will also be deleted
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hope you understood so City language is
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enrolled with only one student so if you
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delete this are they automatically the
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course details will also be deleted
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so that is one drawback that means
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deletion of one data May delete the some
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other data
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okay so previously if it is a c language
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there will be no problem if you delete
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the students are they there will be a
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course title C which was enrolled with a
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hurry but if the case is like this
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if the case is like this that means if
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the course is enrolled with only one
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student if you delete the student
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automatically the course will also be
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deleted if you delete this course the
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student details will also be deleted
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right so such type of anomaly we call it
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as a deletion anomaly
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so
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deletion of course or uh yeah relation
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of course will delete
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student also
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or simply vice versa if you delete the
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student automatically the course will be
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get deleted
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that's called the deletion anomaly and
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updation and only
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updation anomalies so coming to this
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updation anomaly if there is a data
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redundancy automatically this updation
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will be done okay this anomaly will be
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occurs see here we are having the
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redundancy see this is the redundancy we
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are having
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and uh
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this is the redundancy we are having so
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if if the address of a particular
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student Sandeep has been changed that
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should be reflected in two different
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rows
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so hope you understood so there is a
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redundancy column redundancy
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so here
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if the address of a student Sandeep has
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been changed to
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Bangalore so that should be reflected on
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other rows which are related to this
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particular Sunday
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okay so we need to update the two
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different rows so one updating one row
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will not reflect on another row so here
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what what happens in the first row the
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assembly belongs to Bangalore in the
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second row the Sunday belongs to
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babatlan which shares the common student
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ID
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okay common student ID so 100 student ID
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100 belongs to Bangalore in one Tuple
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belongs to babatlin
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so which is nothing but update anomaly
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update anomaly so there is a redundancy
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so if one uh Tuple has been changed
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updated that should not that will not
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reflect on the other thing other tuples
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right so here
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change of address
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change of address
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for student ID
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101
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will not
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reflect on
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other tuples
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other triples and here we are having two
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different uh I mean red energy and here
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also we are having redundancy so which
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belongs to same student ID right so if
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you change this one so it should reflect
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on the second one also but it doesn't
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happens manually we have to change
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another rows also which are related to
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this particular one zero three together
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so such type of anomaly we called as an
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updation anomaly updation anomaly right
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so this is just because of a poor design
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okay a very bad design
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so in order to avoid such anomalies we
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need we need to move with the next one
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that is a normalization so there will
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split the tables which will avoid these
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type of anomalies
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okay we'll split this complete table
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okay and we'll relate them we'll relate
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them
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so that's why
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by splitting the tables we can avoid the
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anomalies concept overcome the anomalies
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that means of false occurred in the
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database
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right so hope you understood this one so
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if you are having any doubts regarding
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this anomalies concept feel free to post
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your doubts in the comment section
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definitely I will try to clarify all
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