How Can I Concisely Update Existing Records When Inserting with Conflicting Unique Keys?

Insert with On Duplicate Key Update: A Concise Approach

When working with databases, it's often desirable to update existing records when attempting to insert new ones with conflicting unique keys. This is where the "ON DUPLICATE KEY UPDATE" clause comes in handy.

The Situation

Suppose you have a table with a unique index on the "id" field and you want to insert a new record while ensuring that if the id already exists, the corresponding record is updated.

Conventional Approach

The conventional approach involves specifying all the field values in the UPDATE clause, as shown below:

INSERT INTO table (id, a, b, c, d, e, f, g) VALUES (1, 2, 3, 4, 5, 6, 7, 8)
ON DUPLICATE KEY UPDATE a=2, b=3, c=4, d=5, e=6, f=7, g=8;

This approach works well but can become verbose if you have a large number of columns.

Concise Alternative

To simplify the UPDATE clause, you can use the "VALUES" keyword to specify the new values for the updated fields. This eliminates the need to repeat the column names:

INSERT INTO table (id, a, b, c, d, e, f, g) VALUES (1, 2, 3, 4, 5, 6, 7, 8)
ON DUPLICATE KEY UPDATE a=VALUES(a), b=VALUES(b), c=VALUES(c), d=VALUES(d), e=VALUES(e), f=VALUES(f), g=VALUES(g);

This approach is more concise and still achieves the same result.

Getting the Last Inserted ID

If you need to retrieve the ID of the newly inserted or updated record, you can use the backend-specific method provided by your database or framework. For example, in LuaSQL, you can use the "conn:getlastautoid()" function to fetch the last auto-generated ID.

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