In this tutorial, you have learned about the PostgreSQL upsert feature using the INSERT ON CONFLICT statement. The following statement verifies the upsert: Suppose, you want to concatenate the new email with the old email when inserting a customer that already exists, in this case, you use the UPDATE clause as the action of the INSERT statement as follows: INSERT INTO customers ( name, email)ĭO UPDATE SET email = EXCLUDED.email || ' ' || customers.email Code language: SQL (Structured Query Language) ( sql ) The following statement is equivalent to the above statement but it uses the name column instead of the unique constraint name as the target of the INSERT statement. The statement specified that if the customer name exists in the customers table, just ignore it (do nothing). ON CONFLICT ON CONSTRAINT customers_name_keyĭO NOTHING Code language: SQL (Structured Query Language) ( sql ) Suppose Microsoft changes the contact email from to, we can update it using the UPDATE statement. However, to demonstrate the upsert feature, we use the following INSERT ON CONFLICT statement: INSERT INTO customers ( NAME, email) ( 'Intel', ' ') Code language: SQL (Structured Query Language) ( sql ) The following INSERT statement inserts some rows into the customers table. The name column has a unique constraint to guarantee the uniqueness of customer names. The customers table consists of four columns: customer_id, name, email, and active. ) Code language: SQL (Structured Query Language) ( sql ) The following statement creates a new table called customers to demonstrate the PostgreSQL upsert feature. If you are also working with MySQL, you will find that the upsert feature is similar to the insert on duplicate key update statement in MySQL. If you are using an earlier version, you will need a workaround to have the upsert feature. Notice that the ON CONFLICT clause is only available from PostgreSQL 9.5. WHERE condition – update some fields in the table. DO NOTHING – means do nothing if the row already exists in the table.To use this statement, we recommend that you update your instance to the latest minor version. WHERE predicate – a WHERE clause with a predicate. The COPY ON CONFLICT statement is supported only by AnalyticDB for PostgreSQL V6.0 instances in minor version 20210528 or later.ON CONSTRAINT constraint_name – where the constraint name could be the name of the UNIQUE constraint.This means that the command will not be allowed to affect any single existing row. Write to return all columns of the inserted or updated row (s). The expression can use any column names of the table named by tablename. In this statement, the target can be one of the following: INSERT with an ON CONFLICT DO UPDATE clause is a deterministic statement. An expression to be computed and returned by the INSERT command after each row is inserted or updated. PostgreSQL added the ON CONFLICT target action clause to the INSERT statement to support the upsert feature. ON CONFLICT target action Code language: SQL (Structured Query Language) ( sql ) To use the upsert feature in PostgreSQL, you use the INSERT ON CONFLICT statement as follows: INSERT INTO table_name(column_list) That is why we call the action is upsert (the combination of update or insert). The idea is that when you insert a new row into the table, PostgreSQL will update the row if it already exists, otherwise, it will insert the new row. The count is the number of rows inserted or updated.oid is always 0 (it used to be the OID assigned to the inserted row if count was exactly one and the target table was declared WITH OIDS and 0 otherwise, but creating a table WITH OIDS is not supported anymore). In relational databases, the term upsert is referred to as merge. On successful completion, an INSERT command returns a command tag of the form. As noted, the ON CONFLICT clause is the one that covers the behavior you describe.Summary: in this tutorial, you will learn how to use PostgreSQL upsert feature to insert or update data if the row that is being inserted already exists in the table. Then, go read the INSERT documentation since what you are doing is first and foremost an insert, not an update, as a literal reading of your description makes clear. (If that isn't your choice you should solve the "lack of a natural primary key" before moving forward and trying to code logic that requires a primary key). Ignoring questions of appropriateness if that is your choice you've found your unique constraint for the table. In this case you seem to be using the vehicle's license plate to determine identity. Make/Model/Year, on an "autos" table, which purports to list specific vehicles, would indeed not be unique. How did you follow the documentation and come up with that - the linked page covers UPDATE and at no time is an INSERT mentioned (well, the savepoint example I suppose, but this doesn't look anything like that either)?
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