Note SQLite users should be aware of some caveats when using bulk inserts.Specifically, your SQLite3 version must be 220.127.116.11 or newer to take advantage of the bulk insert API.DECLARE @e Name varchar(50), @job varchar(50) DECLARE Mynew Cursor CURSOR -- Declare cursor name FOR Select e Name, job FROM emp where deptno =10 OPEN Mynew Cursor -- open the cursor FETCH NEXT FROM Mynew Cursor INTO @e Name, @job PRINT @e Name ' ' @job -- print the name WHILE @@FETCH_STATUS = 0 BEGIN FETCH NEXT FROM Mynew Cursor INTO @ename, @job PRINT @e Name ' ' @job -- print the name END CLOSE Mynew Cursor DEALLOCATE Mynew Cursor Cursor might used for retrieving data row by row act like a looping statement(ie while or for loop). Cursor works with the rows of the result set sequentially - row by row.To use cursors in SQL procedures, you need to do the following: 1. A cursor can be viewed as a pointer to one row in a set of rows and can only reference one row at a time, but can move to other rows of the result set as needed.Recursive CTEs can be useful when, for example, you have a tree data-structure represented by a parent-link foreign key.Suppose, for example, that we have a hierarchy of categories for an online bookstore.Additionally, by default SQLite limits the number of bound variables in a SQL query to Depending on the number of rows in your data source, you may need to break it up into chunks.SQLite in particular typically has a limit of 999 variables-per-query (batch size would then be roughly 1000 / row length).
I want to use a database cursor; first I need to understand what its use and syntax are, and in which scenario we can use this in stored procedures?
This caching can problematic, however, when you plan to iterate over a large number of rows.
To reduce the amount of memory used by peewee when iterating over a query, use the When iterating over a large number of rows that contain columns from multiple tables, peewee will reconstruct the model graph for each row returned. For example, if we were selecting a list of tweets along with the username and avatar of the tweet’s author, Peewee would have to create two objects for each row (a tweet and a user).
Let’s assume you have a tagging application and want to find tags that have a certain number of related objects.
For this example we’ll use some different models in a that deactivates all user accounts whose registration has expired.