Updating rows in sql
The rowid_script shown below gives an example of this.
The script creates a test table as a copy of the all_objects view and then loops through the table twice updating each row at a time.
By using a noname PL/SQL block, this can be achieved. If anyone has a solution to use it in a SELECT Command, I would be interested. For example, if my table T has one column c1 which contains "1" as value for all and now I update all rows for that column to "2", how will partitioning by null help?
I think that Ali H's point is that it's not necessary to assign it to a variable until you have another SQL statement that would affect the row count.
For example, you can use the MERGE statement to perform the following operations: It is important to understand how the source and target data are merged into a single input stream and how additional search criteria can be used to correctly filter out unneeded rows.
Otherwise,you might specify the additional search criteria in a way that produces incorrect results.
Rows in the source are matched with rows in the target based on the join predicate specified in the ON clause. One insert, update, or delete operation is performed per input row.
During small operations this overhead is not noticeable, but it can cause a significant overhead for batch operations.
When executing the query manually it tells me how many rows were affected, I want to get that number in PL/SQL.
The basic problem is that SQL%ROWCOUNT is a PL/SQL variable (or function), and cannot be directly accessed from an SQL command. 1 client updated for 10 After running update statement if you check the count on what you actually updated - This doesn't give any generic solution.
Each rowid represents the physical address of a row within the database and as such is the quickest way to access the row.
In processes where data is rapidly selected and updated the use of rowids can improve performance.