Unlike REPLACE – an inherently destructive command due to the DELETE commands it performs when necessary – using INSERT. ON DUPLICATE KEY UPDATE statement and clause. UPSERT in SQLite follows the syntax established by PostgreSQL, with generalizations. The alternative (and generally preferred) method for INSERTING into rows that may contain duplicate UNIQUE or PRIMARY KEY values is to use the INSERT. UPSERT is a clause added to INSERT that causes the INSERT to behave as an UPDATE or a no-op if the INSERT would violate a uniqueness constraint. More information on using REPLACE can be found in the official documentation. Notice that even though we only altered one row, the result indicates that two rows were affected because we actually DELETED the existing row then INSERTED the new row to replace it. UPSERT is a clause added to INSERT that causes the INSERT to behave as an UPDATE or a no-op if the INSERT would violate a uniqueness constraint. The common approach: ON DUPLICATE KEY UPDATE The result of that approach, disturbingly: Insert unless the PRIMARY or any UNIQUE key exists, otherwise update What can go horribly wrong with ON DUPLICATE KEY UPDATE You insert a supposedly new record, with a new PRIMARY key value (say a UUID), but you happen to have a duplicate value for its. Seuss', 1960 ) Query OK, 2 rows affected ( 0.
#Sqlite insert update on duplicate key how to
Is there a way to insert duplicate row I heard about the rowid may do the tricks for me but Im not sure how to use it. I noticed that I was not able to insert duplicate records. Mysql > REPLACE INTO books ( id, title, author, year_published ) VALUES ( 1, 'Green Eggs and Ham', 'Dr. Hi I have a simple table without specifying primary key or unique key. The obvious purpose is to execute a large number of INSERT statements for a combination of data that is both already existing in the database as well as new data coming into the system.įor example, our books table might contain a few records already: This means that an INSERT IGNORE statement which contains a duplicate value in a UNIQUE index or PRIMARY KEY field does not produce an error, but will instead simply ignore that particular INSERT command entirely. Using INSERT IGNORE effectively causes MySQL to ignore execution errors while attempting to perform INSERT statements. MySQL provides a number of useful statements when it is necessary to INSERT rows after determining whether that row is, in fact, new or already exists.īelow we’ll examine the three different methods and explain the pros and cons of each in turn so you have a firm grasp on how to configure your own statements when providing new or potentially existing data for INSERTION.
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