A primary key is a field in a database table that uniquely identifies each row/record. Primary keys must have distinct values. NULL values are not allowed in a primary key column. A table can only have one primary key, which can be made up of one or more fields.
The column or columns that hold values that uniquely identify each row in a table are known as primary keys. For Optim to insert, update, restore, or delete data from a database table, the table must contain a primary key. Optim makes use of database-defined primary keys.
Text and ntext columns cannot have a primary key. However, you may achieve the same functionality by using a varchar datatype (8000). The only difference is that this column can now hold up to 8000 characters.
A primary key is a field (or combination of fields) in a table that has values that are unique across all rows. Because each record has a unique value for the key, values of the key can be used to refer to whole records. There can only be one primary key per table.
A surrogate key is a one-of-a-kind identifier for a client's business entity or a database object. Natural keys cannot always be used to establish a unique table primary key. When a data modeller or architect chooses to use surrogate or helping keys for a table in the LDM, this is what happens.
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Durgesh Rajbhar
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i wan a pdf of this course
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Vinayak Ghatage
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Best One
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Khushi Kumari Yadav
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how can i get pdf of this session
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Arvind Kumar
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very nice course for begginer to under stand
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hemant
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Hello sir, explaination is excellent. I have a request please send the db in excel or SQL file
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Juboraj Juboraj
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Explain details & easy to understand.
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Aman Kanaujia
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All good , but provide the data also for the assignment , Without data the interest is less day by day from the course. So, try to solve this problem as asap.
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Snehil
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Everything is good but keyboard sounds more harsh and overlap your voice whereas this course is best.
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FAROOK MOHAMMAD
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Hello sir, explaination is excellent. I have a request please send the db in excel or SQL file.
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Hari Prakash
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In SQL Join Function's 2nd video - Teacher's voice dose not match with background content that are plays
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