cursor

问题 What is the advantage of using FAST_FORWARD for defining a cursor? Is it better for performance? why? 回答1: The definition from MSDN is: Specifies a FORWARD_ONLY, READ_ONLY cursor with performance optimizations enabled . FAST_FORWARD cannot be specified if SCROLL or FOR_UPDATE is also specified. FAST_FORWARD and FORWARD_ONLY are mutually exclusive; if one is specified the other cannot be specified. I've boldened the key bit. It can support these "performance optimisations" because it does not

问题 What is the advantage of using FAST_FORWARD for defining a cursor? Is it better for performance? why? 回答1: The definition from MSDN is: Specifies a FORWARD_ONLY, READ_ONLY cursor with performance optimizations enabled . FAST_FORWARD cannot be specified if SCROLL or FOR_UPDATE is also specified. FAST_FORWARD and FORWARD_ONLY are mutually exclusive; if one is specified the other cannot be specified. I've boldened the key bit. It can support these "performance optimisations" because it does not

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I want to pass a DataDable to a stored procedure as parameter cointaning the columns below: Supp_Id int Del_Methode_Id int Ord_Ammount int Promo_Id int Discount_Ammount Money Now I want to use this datatable in stored procedure and want to declare a cursor on it. And use that cursor to insert values into the

问题 I am developing an Android application where I would like to move the "mouse" pointer/cursor on an Android tablet. I know this is possible because when I connect a mouse (USB or BT) to an Android tablet (Honeycomb+), a cursor appears and I can interact with the tablet using the mouse only. I would like to control that mouse from Java on the Tablet. I already have a second device that can communicate the tablet and which can stream pointer coordinates to it. And no I can't use bluetooth. The

问题 I have 2 tables- student and studLoad both having 2 fields studID and studName . I want to load data from student table into stuLoad table. If the data already exists in the studLoad table, then it should be updated else it should be inserted. following is my code to do so: create or replace procedure studentLoad is v_id student.studID%type; v_name student.studName%type; v_sn studLoad.studName%type; cursor cur_load is select * from student; begin open cur_load; loop fetch cur_load into v_id,v

问题 There seems to be a 1MB limit on Android's Cursor Window size which limits the ability to read BLOBs from SQLite. I know you may say we should not store BLOBs in database but by definition, BLOB is considered a Binary Large Object and if there was no need to store them in database, there was no need to implement such object type in any database engines. The 1 MB limit on the implementation of Cursor however, seems to be insufficient in almost all cases. I need to store my binary data for

问题 We are troubled by eventually occurring cursor not found exceptions for some Morphia Queries asList and I've found a hint on SO, that this might be quite memory consumptive. Now I'd like to know a bit more about the background: can sombody explain (in English), what a Cursor (in MongoDB) actually is? Why can it kept open or be not found? The documentation defines a cursor as: A pointer to the result set of a query. Clients can iterate through a cursor to retrieve results. By default, cursors

问题 From time to time, I'm executing raw queries using connection.cursor() instead of using ORM (since it is definitely not a silver bullet). I've noticed that in several places I don't call explicit cursor.close() after I'm done with database. So far, this hasn't result into any errors, or performance issues. I'm wondering what kind of problems could I possibly have without closing the cursor explicitly, what can go wrong? As far as I understand, connection and cursor in Django follow "Python

问题 I have setup 2 test contacts in my emulator. I'm running the following query, it should pick them both out, populate my domain object, and add to a list. The output at the bottom should therefore be 2, but it is 5, why is this? (cursor.getCount() is 5 instead of 2) I have stepped through each iteration of the while loop and it is retreving the same contact multiple times, but with different values for POSTCODE , such as the phone number ContentResolver cr = getContentResolver(); Cursor cursor

问题 Let's say I got a table, something like this: ID | TITLE 1 | AAA 2 | BBB 3 | CCC 4 | DDD 5 | EEE ... ... I want to perform a query, using IN opeator, while preserving the order of the IN Arguments database.query("some_table", null, ID + " IN("+ idsStr+")", null, null, null, null); For example, if the query is "select from some_table where id in (4,1,5) ...(order by???)", I want that the returned cursor to be sorted as 4,1,5 Is it possible? how? 回答1: EDIT: Tested, works: SELECT * FROM books