What is the replacement for cursor in SQL Server?

What is the replacement for cursor in SQL Server?

Temporary tables have been in use for a long time and provide an excellent way to replace cursors for large data sets. Just like table variables, temporary tables can hold the result set so that we can perform the necessary operations by processing it with an iterating algorithm such as a ‘while’ loop.

How do I change the cursor in SQL?

You have to mention which column you are going to update (or all columns in your selection will be updatable) and you have to use ‘where current of ‘ in your update statement.

Why cursor is not recommended in SQL?

Cursors could be used in some applications for serialized operations as shown in example above, but generally they should be avoided because they bring a negative impact on performance, especially when operating on a large sets of data.

Which is better cursor or while loop in SQL Server?

While SQL While loop is quicker than a cursor, reason found that cursor is defined by DECLARE CURSOR. Every emphasis of the loop will be executed inside system memory and consuming required server assets.

Which is better cursor or temp table?

So if you can use set-based operations to fill and use your temporary tables, I would prefer that method over cursors every time. Temp tables can be fine or bad depending on the data amount and what you are doing with them. They are not generally a replacement for a cursor.

How do I change my cursor?

You can update rows of data as you retrieve them by using a cursor. On the select-statement, use FOR UPDATE OF followed by a list of columns that may be updated. Then use the cursor-controlled UPDATE statement. The WHERE CURRENT OF clause names the cursor that points to the row you want to update.

What are the different types of cursor in SQL Server?

SQL Server supports three cursor implementations.

• Transact-SQL cursors. Transact-SQL cursors are based on the DECLARE CURSOR syntax and used mainly in Transact-SQL scripts, stored procedures, and triggers.
• Application programming interface (API) server cursors.
• Client cursors.
• Forward-only.
• Static.
• Keyset.
• Dynamic.

What is the difference between cursor temp table and table variable?

This biggest difference is that a CTE can only be used in the current query scope whereas a temporary table or table variable can exist for the entire duration of the session allowing you to perform many different DML operations against them.

Should I use cursors or joins in SQL Server?

Relational database management systems including SQL Server are very good at processing data in sets. However, if you want to process data on row-by-row basis rather than in sets, cursors are your only choice. Unfortunately, cursors are extremely slow and so where possible should be replaced with JOINS.

What is the use of loop and cursor in SQL?

SQL While loop and cursor are the most common approach to repeat a statement on condition-based or determined limits. Loop and cursor can be utilized in a circumstance to deal with row-based processing in T-SQL. We generally observe moderate execution of old made procedures, which are composed of using loop and cursors.

How to move the cursor to the first row in SQL?

To move the cursor to the first row we use the FETCH NEXT command. We then use the INTO statement to fetch data from the cursor and insert it into our local variables. To move the cursor to next row we again use FETCH NEXT. A better approach is to use a loop and call FETCH NEXT within the loop so that the cursor can iterate over all the rows.

Can we replace SQL while loop and cursor with recursive CTE?

We can supplant SQL While loop and cursor with recursive CTE to make it straightforward code structure but query performance-wise, no strange.