Updating multiple tables in pl sql
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.
and we could persuade the database server to apply those updates to the target table?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”.Use the SQL Server Management Studio (SSMS) Table Designer to create, edit, or delete tables, columns, keys, indexes, relationships, and constraints.A requirement arises in many systems to update multiple SQL database rows.
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The differences in syntax are quite dramatic compared to other database systems like MS SQL Server or My SQL. Updates based on two or more common columns are normally used for tables where multiple columns work together as a primary key (known as composite primary key).