Sql updating primary key value
If a table has a primary key defined on any field(s), then you cannot have two records having the same value of that field(s).
Note − You would use these concepts while creating database tables.
Here is the syntax to define the ID attribute as a primary key in a CUSTOMERS table.
NOTE − If you use the ALTER TABLE statement to add a primary key, the primary key column(s) should have already been declared to not contain NULL values (when the table was first created).
Some of the common ones are: In these cases, the UPDATE statement execution stops and the UPDATE generates an error.
No rows from the UPDATE statement are saved into the table, even those rows that didn’t generate an error.
The UPDATE statement is complex and there are many elements to consider. For a full list check out the UPDATE (Transact-SQL) article.
Keep in mind that when updating data in columns whose data type is CHAR, VARCHAR, or VARBINARY, the padding or truncation of data depends upon the SET ANSI_PADDING setting.
There are several common reason an UPDATE statement may fail.Though this article uses the Adventure Works database for its examples, I’ve decided to create an example table for use within the database to help better illustrate the examples. The SQL UPDATE statement is used to change column values.