Updating a table in pl sql
Updating a table in pl sql - dating on the sunshine coast
Personally, if it wasn't for the 0.001% of the time where there's no other solution, I don't even think it should even be an available function in T-SQL.T-SQL is designed to be set-based, so it works on entire sets of data as a whole; it should NOT be used to work on data line-by-line.
There are 2 syntaxes for an update query in Oracle depending on whether you are performing a traditional update or updating one table with data from another table.To get started using a Nested Table, create a code block that declares a nested table type and instantiates a nested table of this created type (Lines 2 & 4).This code iterates through a FOR Loop 3 times to show that the Nested Table has been initialized with 3 Null members.Since you can't list more than one table in the Oracle UPDATE statement, you can use the Oracle EXISTS clause.This article describes how to create and use the single dimensional structures known as nested tables.The values of the Nested table are then assigned and another FOR Loop iterates 3 times to output the values of the Nested Table once again. 3 lines with no results from the null values and 3 lines with the populated data.
The next example declares a type of Nested Table on line 2 and then declares a variable of this new type, Animal_Table on line 3 again.If your table t1 and it's backup t2 have many columns, here's a compact way to do it.In addition, my related problem was that only some of the columns were modified and many rows had no edits to these columns, so I wanted to leave those alone - basically restore a subset of columns from a backup of the entire table. This means that you have to select on all the fields which comprise a unique key -- a non-unique primary key is not sufficient.Without uniqueness, you are reduced to something like @Paul Karr's loop -- and if there is not a unique correlation, then more than one target row may be updated for each source row.SQL courses meet the most demanding needs of the business world for advanced education in a cost-effective manner.