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Bulk updating multiple columns in oracle phonedating com

But we can group the updates according to the value being set, and then do one UPDATE statement per distinct value.In this case there are two distinct values, so we can do it in two UPDATE statements: So we can reduce the number of queries from five to two. But the extent to which this helps us reduces as the proportion of distinct SET values goes up.It is relatively straightforward to populate a table with multiple rows with just one query (or at least, far fewer queries than the number of rows desired).So, given a list of updates to apply we could effect them using the following steps: So in the example above we can reduce five statements to four. But now the number of statements is no longer directly dependent on the number of rows requiring updates.Even if we wanted to update a thousand rows with different values, we could still do it with four statements.

The ‘where’ parameter can be used to specify a global condition, e.g. Another thing which we may want to do is update a column with the same value for all rows being updated. Rather than have to specify the same value over and over again, we can use the ‘set’ parameter.In this case, will spot that the target values are all 1200, and will effect the desired changes using a single UPDATE statement as described above.(It will use placeholders and parameter binding if it thinks it’s appropriate.) If given our second example with two distinct values, will spot that there are two distinct values, 12, and will effect this with two UPDATE statements as described above.A more effective solution to this problem is to attempt to reduce the number of UPDATE statements.Let us start with a simple table: UPDATE staff SET salary = 1200 WHERE name = ' Bob'; UPDATE staff SET salary = 1200 WHERE name = ' Jane'; UPDATE staff SET salary = 1200 WHERE name = ' Frank'; UPDATE staff SET salary = 1200 WHERE name = ' Susan'; UPDATE staff SET salary = 1200 WHERE name = ' John'; UPDATE staff SET salary = 1200 WHERE name = ' Bob'; UPDATE staff SET salary = 1250 WHERE name = ' Jane'; UPDATE staff SET salary = 1200 WHERE name = ' Frank'; UPDATE staff SET salary = 1250 WHERE name = ' Susan'; UPDATE staff SET salary = 1200 WHERE name = ' John'; We are no longer setting all the salary fields to the same value, so we can’t collapse it into a single statement.So whereas previously we specified the matching column using a scalar, when there is more than one column to match, we use an Array Ref.Similarly, let’s say we want to update two fields, salary and bonus.This is the intention of UPDATE staff SET salary = 1200 WHERE name = ' Bob'; UPDATE staff SET salary = 1200 WHERE name = ' Jane'; UPDATE staff SET salary = 1200 WHERE name = ' Frank'; UPDATE staff SET salary = 1200 WHERE name = ' Susan'; UPDATE staff SET salary = 1200 WHERE name = ' John'; “key_columns” specifies the columns which will be used to identify rows which need to be updated (using WHERE). The first element provides the value of the column (specified by “key_columns”) to identify the row to be updated.“value_columns” specifies the columns which will be updated (using SET). The second element provides the value to be SET in the column specified by “value_columns”.The traditional advice for improving performance for multiple UPDATE statements is to “prepare” the required query once, and then “execute” the prepared query once for each row requiring an update.But in many cases this only provides a modest improvement as each UPDATE operation still requires a round-trip communication with the database server.

367 comments

  1. You need not specify the partition name when updating values. multiple columns in the update. on using the BULK COLLECT clause to return multiple values.

  2. You can perform multiple bulk copy operations using a single instance of. // Perform an initial count on the destination // table with matching columns.

  3. ORACLE-BASE - Bulk Binds BULK COLLECT. FORALL and Record Processing in Oracle. which have to reference inividual columns of the collection in the where.

  4. How-To Document. How to use the SQL. Oracle SQL Developer provides a SQL Worksheet that you can use to. updating single and multiple records and deleting.

  5. Hello, searched documentation, FAQ and mailing list archives mailing list archive search is volumous - but could not find an answer I would like to be able to.

  6. Tag Bulk Collect Updating Millions of. Bulk Collect. Using rowid to perform bulk updates on the base. This will reduce multiple reads/writes of the same base.

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