Oracle merge returning 12c

Hi all, Thanks in advance. Introduction to the Oracle MERGE statement. The Oracle MERGE statement selects data from one or more source tables and updates or inserts it into a target table. The MERGE statement allows you to specify a condition to determine whether to update data from or insert data into the target table.

Returing clause for oracle merge. RETURNING clause to return ? Taking out bypass_ujvc hint in 12c converting update to merge statements. Domain Model For this article, let’s assume we have the following.

You can then use the package in an anonymous block with your merge statement to capture the id and return it. Note that this is a very simple example and it will not work with array-bound variables unless you rework the package to capture the IDs into a table type. If I get a chance, I may try to put together an example that shows this. The condition can refer only to the data source table.

You can specify this clause by itself or with the merge _update_clause. If you specify both, then they can be in either order. Oracle Database skips the insert operation for all rows for which the condition is not true.

The merge _update_clause specifies the new column values of the target table. Oracle performs this update if the condition of the ON clause is true. If the update clause is execute then all update triggers defined on the target table are activated. How does Oracle merge work?

What is a MERGE statement? A typical scenario for using MERGE would be when you have to synchronize two tables having the same structure but potentially different data sets. This is done by the addition of the ONLINE keywor which also causes local and global indexes to be updated without having to specify the UPDATE INDEXES clause. With it comes a whole host of new features to help you write better, faster applications. Easier, Better, Faster, Stronger JSON.

The returning clause specifies the values return from DELETE, EXECUTE IMMEDIATE, INSERT, and UPDATE statements. You can retrieve the column values into individual variables or into collections. In Oracle 11g, you can merge the content of two partitions only in single DDL.

However, in Oracle 12c , you can merge multiple partitions into one in a single DDL statement. After merging the content of multiple partitions into a single partition, you can drop the original partitions that are merged. It lets you merge two tables in Oracle SQL.

It’s a bit smarter than an INSERT INTO SELECT statement. You can analyse records to see if they match between a source and a target table. Specify the where_clause if you want.

If that merge statement contains plsql in a with clause (a new feature for Oracle 12c ) and (!!) it makes use of bind variables which get their values from a using-clause with the execute immediate, then your session will crash horribly. You will be disconnected from the database. At a high level the merge statement simplifies the syntax, which is essentially a simple insert, if already exists, update.

Sadly, there are some serious performance issues with MERGE , as noted here. A second table is created with updated item and price information. In order to roll all the info into the original catalogtable, merge is use since this is a standard UPDATE-else-INSERT task.

In general, hash joins perform better than sort merge joins because sorting is expensive.