[sqlite] SQLite "INSERT OR REPLACE INTO" vs. "UPDATE ... WHERE"

I've never seen the syntax INSERT OR REPLACE INTO names (id, name) VALUES (1, "John") used in SQL before, and I was wondering why it's better than UPDATE names SET name = "John" WHERE id = 1. Is there any good reason to use one over the other. Is this syntax specific to SQLite?

I'm currently working on such a statement and figured out another fact to notice: INSERT OR REPLACE will replace any values not supplied in the statement. For instance if your table contains a column "lastname" which you didn't supply a value for, INSERT OR REPLACE will nullify the "lastname" if possible (constraints allow it) or fail.

REPLACE INTO table(column_list) VALUES(value_list);

is a shorter form of

INSERT OR REPLACE INTO table(column_list) VALUES(value_list);

For REPLACE to execute correctly your table structure must have unique rows, whether a simple primary key or a unique index.

REPLACE deletes, then INSERTs the record and will cause an INSERT Trigger to execute if you have them setup. If you have a trigger on INSERT, you may encounter issues.

This is a work around.. not checked the speed..

INSERT OR IGNORE INTO table (column_list) VALUES(value_list);

followed by

UPDATE table SET field=value,field2=value WHERE uniqueid='uniquevalue'

This method allows a replace to occur without causing a trigger.

The insert or replace query would insert a new record if id=1 does not already exist.

The update query would only oudate id=1 if it aready exist, it would not create a new record if it didn't exist.