Violation of Unique Value Constraint in MySQL

Q

What Happens If Unique Value Constraints Are Violated in MySQL?

✍: FYIcenter.com

A

If you are inserting a new record that has values violating a unique constraint, you will get an error. Note that primary key column has a unique value constraint by default. The following tutorial exercise gives you some good examples:

mysql> INSERT INTO fyi_links (url) VALUES ('www.other.com');
ERROR 1062 (23000): Duplicate entry '0' for key 1

mysql> INSERT INTO fyi_links VALUES (101, 
  'sql.fyicenter.com', 
  NULL,
  0,
  '2006-04-30');
ERROR 1062 (23000): Duplicate entry '101' for key 1

⇒ Insert Multiple Rows with 1 INSERT Statement in MySQL

⇐ Omitting Columns in INSERT Statements in MySQL

⇑ INSERT, UPDATE and DELETE Statements in MySQL

⇑⇑ MySQL Database Tutorials

2018-01-16, 1592🔥, 0💬

Using Column Default Values in MySQL
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Update Column Values on Multiple Rows in MySQL
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Order of Columns in the SET Clause in MySQL
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Inserting a New Row into a Table in MySQL
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Use Existing Column Values in the SET Clause in MySQL
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Violation of Unique Value Constraint in MySQL
What Happens If Unique Value Constraints Are Violated in MySQL? If you are inserting a new record that has values violating a unique constraint, you will get an error. Note that primary key column has a unique value constraint by default. The following tutorial exercise gives you some good examples:... 2018-01-16, 1593🔥, 0💬

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Creating a Test Table in MySQL
How To Create a Testing Table in MySQL? If you want to practice DML statements, like INSERT, UPDATE and DELETE, you should create a testing table. The tutorial exercise shows you a good example: mysql> CREATE TABLE fyi_links (id INTEGER PRIMARY KEY, url VARCHAR(80) NOT NULL, notes VARCHAR(102... 2018-01-24, 1509🔥, 0💬

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