Original: http://ntk2006.blog.sohu.com/135331235.html
Cursor ConceptCursors provide a flexible way to retrieve and operate data from tables. cursors are mainly used on servers to process SQL statements sent from clients to servers, or data
one. Adaptive cursor Sharing (adaptive Cursor sharing) Description
1.1 ACS Overview
Binding variables Enable Oracle DB to share a single cursor for multiple SQL statements to reduce the amount of shared memory used for parsing SQL statements.
CursorA cursor is a data buffer opened by the system for the user, which holds the results of the SQL statement execution. Each cursor area has a name that allows the user to retrieve the record from the cursor one at a-and assign it to the main
Cursors are evil!
In relational databases, we think about queries in a set. The cursor breaks this rule and changes the way we think about it into a row-by-row approach. For C-like developers, this approach is more comfortable.
The normal way of
Cursors are evil!
In relational databases, we think about queries in a set. The cursor breaks this rule and changes the way we think about it into a row-by-row approach. For C-like developers, this approach is more comfortable.
The normal way of
Cursors are evil!
In relational databases, we think about queries in a set. The cursor breaks this rule and changes the way we think about it into a row-by-row approach. For C-like developers, this approach is more comfortable.
The normal way of
One: Understanding CursorsCursor It enables the user to access the result set returned by SQL Server on a row-by-line basis.One of the main reasons for using cursors is to convert the set operation to a single record processing mode.When data is
An Oracle cursor is divided into a display cursor and an implicit cursor.
Display cursor (Explicit Cursor): A cursor defined in a PL/SQL program, used for querying, is called a display cursor.Implicit cursors (implicit Cursor): A cursor that is
As shown in the Code, the speed of 2 is several times faster.
Public void getcontact (context con ){Cursor cursor = con. getcontentresolver (). Query (contactscontract. Contacts. content_uri,Projection, null, null, query_order_by_name );If (cursor!
IntroductionLet's start with an example of what the cursor concept, steps, and syntax are:?????? Table One originsalary??????????????????????????????????????????????????? Table Two AddsalaryNow there are 2 tables, one is the Originsalary table-the
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.