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  • how to implement undo operation in datagridview

    - by ush
    Hi, I have created one application in c#.net.Using this application we can update datagridview,now i need to implement undo in it plz give me some ideas. private void button29_Click(object sender, EventArgs e) { Datatable dt; dt.RejectChanges(); } using above code i can do undo before updating. but i need a undo feature as in word plz suggest me thanks in advance

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  • Left Join works with table but fails with query

    - by Frank Martin
    The following left join query in MS Access 2007 SELECT Table1.Field_A, Table1.Field_B, qry_Table2_Combined.Field_A, qry_Table2_Combined.Field_B, qry_Table2_Combined.Combined_Field FROM Table1 LEFT JOIN qry_Table2_Combined ON (Table1.Field_A = qry_Table2_Combined.Field_A) AND (Table1.Field_B = qry_Table2_Combined.Field_B); is expected by me to return this result: +--------+---------+---------+---------+----------------+ |Field_A | Field_B | Field_A | Field_B | Combined_Field | +--------+---------+---------+---------+----------------+ |1 | | | | | +--------+---------+---------+---------+----------------+ |1 | | | | | +--------+---------+---------+---------+----------------+ |2 |1 |2 |1 |John, Doe | +--------+---------+---------+---------+----------------+ |2 |2 | | | | +--------+---------+---------+---------+----------------+ [Table1] has 4 records, [qry_Table2_Combined] has 1 record. But it gives me this: +--------+---------+---------+---------+----------------+ |Field_A | Field_B | Field_A | Field_B | Combined_Field | +--------+---------+---------+---------+----------------+ |2 |1 |2 |1 |John, Doe | +--------+---------+---------+---------+----------------+ |2 |2 |2 | |, | +--------+---------+---------+---------+----------------+ Really weird is that the [Combined_Field] has a comma in the second row. I use a comma to concatenate two fields in [qry_Table2_Combined]. If the left join query uses a table created from the query [qry_Table2_Combined] it works as expected. Why does this left join query not give the same result for a query and a table? And how can i get the right results using a query in the left join?

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  • How to run an .exe application in another computer?

    - by ADAM
    I am working on a C# application in Visual Studio 2013. When I run the .exe file from my computer, the application runs very well and all the features work. When I tried to run the .exe on another computer, the database side doesn't work well and the connection with the database couldn't be opened. The SqlConnection is constructed as follows: SqlConnection cn = new SqlConnection("Data Source=ADAM-PC;Initial Catalog=integrationdatabase;Integrated Security=True" I don't know how to change the data source to make the connection with the database established in another computer. How can I solve this problem?

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  • Storing users in a database

    - by EMcKenna
    Im wondering whats the best way of storing different types of users in my database. I am writing an application that has 4 main user types (admin, school, teacher, student). At the moment I have a table for each of these but i'm not sure thats the best way of storing user information. For instance... Allowing students to PM other student is simple (store sender and receiver student_id) but enabling teachers to PM students requires another table (sender teacher_id, sender student_id). Should all users be stored in one users table with a user_type field? If so, the teacher / student specific information will still have to be stored in another table. users user_id, password_hash, user_type students user_id, student_specific_stuff... teachers user_id, teacher_specific_stuff... How do I stop a user who has a user_type = student from being accidentally being entered into the teachers table (as both have a user_id) Just want to make sure I get the database correct before i go any further. Thanks...

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  • Filtering with joined tables

    - by viraptor
    I'm trying to get some query performance improved, but the generated query does not look the way I expect it to. The results are retrieved using: query = session.query(SomeModel). options(joinedload_all('foo.bar')). options(joinedload_all('foo.baz')). options(joinedload('quux.other')) What I want to do is filter on the table joined via 'first', but this way doesn't work: query = query.filter(FooModel.address == '1.2.3.4') It results in a clause like this attached to the query: WHERE foos.address = '1.2.3.4' Which doesn't do the filtering in a proper way, since the generated joins attach tables foos_1 and foos_2. If I try that query manually but change the filtering clause to: WHERE foos_1.address = '1.2.3.4' AND foos_2.address = '1.2.3.4' It works fine. The question is of course - how can I achieve this with sqlalchemy itself?

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  • Postgresql count+sort performance

    - by invictus
    I have built a small inventory system using postgresql and psycopg2. Everything works great, except, when I want to create aggregated summaries/reports of the content, I get really bad performance due to count()'ing and sorting. The DB schema is as follows: CREATE TABLE hosts ( id SERIAL PRIMARY KEY, name VARCHAR(255) ); CREATE TABLE items ( id SERIAL PRIMARY KEY, description TEXT ); CREATE TABLE host_item ( id SERIAL PRIMARY KEY, host INTEGER REFERENCES hosts(id) ON DELETE CASCADE ON UPDATE CASCADE, item INTEGER REFERENCES items(id) ON DELETE CASCADE ON UPDATE CASCADE ); There are some other fields as well, but those are not relevant. I want to extract 2 different reports: - List of all hosts with the number of items per, ordered from highest to lowest count - List of all items with the number of hosts per, ordered from highest to lowest count I have used 2 queries for the purpose: Items with host count: SELECT i.id, i.description, COUNT(hi.id) AS count FROM items AS i LEFT JOIN host_item AS hi ON (i.id=hi.item) GROUP BY i.id ORDER BY count DESC LIMIT 10; Hosts with item count: SELECT h.id, h.name, COUNT(hi.id) AS count FROM hosts AS h LEFT JOIN host_item AS hi ON (h.id=hi.host) GROUP BY h.id ORDER BY count DESC LIMIT 10; Problem is: the queries runs for 5-6 seconds before returning any data. As this is a web based application, 6 seconds are just not acceptable. The database is heavily populated with approximately 50k hosts, 1000 items and 400 000 host/items relations, and will likely increase significantly when (or perhaps if) the application will be used. After playing around, I found that by removing the "ORDER BY count DESC" part, both queries would execute instantly without any delay whatsoever (less than 20ms to finish the queries). Is there any way I can optimize these queries so that I can get the result sorted without the delay? I was trying different indexes, but seeing as the count is computed it is possible to utilize an index for this. I have read that count()'ing in postgresql is slow, but its the sorting that are causing me problems... My current workaround is to run the queries above as an hourly job, putting the result into a new table with an index on the count column for quick lookup. I use Postgresql 9.2.

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  • How to generate a transaction number?

    - by 001
    I was thinking of formatting it like this TYYYYMMDDNNNNNNNNNNX (1 character + 19 digits) Where T is type YYYY is year MM is month DD is day N is sequencial number X is check digit The problem is, how do I generate the sequencial number? since my primary key is not an auto increment integer value, if it was i would use that, but its not. EDIT can I have the sequencial number resets itself after 1 day (24hours). P201012080000000001X <-- first transaction of 2010/12/08 P2010120810000000002X <--- second transaction of 2010/12/08 P201012090000000001X <--- First transaction of 2010/12/09 (X is the check digit)

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  • SQLAlchemy & Complex Queries

    - by user356594
    I have to implement ACL for an existing application. So I added the a user, group and groupmembers table to the database. I defined a ManyToMany relationship between user and group via the association table groupmembers. In order to protect some ressources of the app (i..e item) I added a additional association table auth_items which should be used as an association table for the ManyToMany relationship between groups/users and the specific item. item has following columns: user_id -- user table group_id -- group table item_id -- item table at least on of user_id and group_id columns are set. So it's possible to define access for a group or for a user to a specific item. I have used the AssociationProxy to define the relationship between users/groups and items. I now want to display all items which the user has access to and I have a really hard time doing that. Following criteria are used: All items which are owned by the user should be shown (item.owner_id = user.id) All public items should be shown (item.access = public) All items which the user has access to should be shown (auth_item.user_id = user.id) All items which the group of the user has access to should be shown. The first two criteria are quite straightforward, but I have a hard time doing the 3rd one. Here is my approach: clause = and_(item.access == 'public') if user is not None: clause = or_(clause,item.owner == user,item.users.contains(user),item.groups.contains(group for group in user.groups)) The third criteria produces an error. item.groups.contains(group for group in user.groups) I am actually not sure if this is a good approach at all. What is the best approach when filtering manytomany relationships? How I can filter a manytomany relationship based on another list/relationship? Btw I am using the latest sqlalchemy (6.0) and elixir version Thanks for any insights.

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  • Meaning of tA tC and tP

    - by Greg Wiley
    If this is a duplicate I appoligize, but looking for two-letter strings is quite hard in any search. I'm looking for the meaning of tA tC and tP in the context of a mysql query. And in the spirit of "teaching a man how to fish" it would be great if you could point me in the right direction of where to find this info in the future. Edit: The Query $wpdb->get_row($wpdb->prepare("SELECT tA.* FROM ".AMYLITE_ADS." tA, ".AMYLITE_ADS_CAMPAIGNS." tC, ".AMYLITE_PACKAGES." tP WHERE tA.id=tC.ad_id AND tC.campaign_id=tP.campaign_id AND tP.zone_id=%d AND tP.date_end>CURDATE() GROUP BY tA.id ORDER BY RAND()", $zone->id));

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  • slow record deletion with large ntext values

    - by asking
    I'm having trouble deleting some records via a stored procedure from a table in SQLServer 2008R2 that has ntext columns. The stored proc is timing out and running the query directly takes a very long time. The initial query was a straight "delete from y where x = z" and I've also tried running it in batches of 1000 with transactions but it is still slow and timing out in a stored proc. The majority of the records in the table will not be deleted each time (it's not just a once-off query but will be run other times). The ntext columns are not used in the where clause and I can't change the column types. Any suggestions on the quickest way to delete records with large ntext values? Thanks

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  • select from varchar2 column with numeric value sometimes gives invalid number error

    - by Rene
    I'm trying to understand why, on some systems, I get an invalid number error message when I'm trying to select a value from a varchar2 column while on other systems I don't get the error while doing the exact same thing. The table is something like this: ID Column_1 Column_2 1 V text 2 D 1 3 D 2 4 D 3 and a query: select ID from table where column_1='D' and column_2 = :some_number_value :some_number_value is always numeric but can be null. We've fixed the query: select ID from table where column_1='D' and column_2 = to_char(:some_number_value) This original query runs fine on most systems but on some systems gives an "invalid number" error. The question is why? Why does it work on most systems and not on some?

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  • Retrieving Top 10 rows ans sum all others in row 11

    - by Mario
    Hello all, I have the following query that retrieve the number of users per country; SELECT C.CountryID AS CountryID, C.CountryName AS Country, Count(FirstName) AS Origin FROM Users AS U INNER JOIN Country AS C ON C.CountryID = U.CountryOfOrgin GROUP BY CASE C.CountryName, C.CountryID What I need is a way to get the top 10 and then sum all other users in a single row. I know how to get the top 10 but I`m stuck on getting the remaining in a single row. Is there a simple way to do it? For example if the above query returns 17 records the top ten are displayed and a sum of the users from the 7 remaining country should appear on row 11. On that row 11 the countryid would be 0 and countryname Others Thanks for your help!

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  • What is wrong with this connection string?

    - by Hakan
    Can any one help me with this connection string. I can't manage how to fix. Dim constring As String Dim con As SqlCeConnection Dim cmd As SqlCeCommand constring = "(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase) + \\database.sdf;Password=pswrd;File Mode=shared read" con = New SqlCeConnection() con.Open() Thanks

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  • How Can I Reference Multiple Primary Keys For A Vector Type Primary Key

    - by AndreiC
    Hi, I have the following scenario: a table of projects and a table of persons, working on one or serveral projects. Also, I have a project id column (of type int), in the first table, which is a primary key there and I have a vector of project ids, as a column of type int, in my second table (persons), that references primary keys from the first table. What is the correct syntax for referencing multiple primary keys, from a vector foreign key. This is the way I am trying to create the table, but I am not sure what to place at the indicated line: CREATE TABLE Persons( Person_Id int, ..., ProjectsList int[], FOREIGN KEY (ProjectsList) REFERENCES Projects(Project_id) -- not sure what how to define the link here ); I hope my explanations are not over-complicated. Thank you in advance for helping!

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  • what type of errors can we handle using system define unnamed exception in sqlplus?

    - by Aspirant
    I have been trying to access the below code DECLARE N_DEPTNO DEPT.DEPTNO %TYPE :=&DEPT_NUM; V_DNAME DEPT.DNAME %TYPE; NOT_ENOUGH_VALUES EXCEPTION; PRAGMA EXCEPTION_INIT(NOT_ENOUGH_VALUES,-06502); BEGIN SELECT DNAME,LOC INTO DNAME FROM DEPT WHERE DEPTNO = N_DEPTNO; DBMS_OUTPUT.PUT_LINE('Successfully Fetched !!'); EXCEPTION WHEN NOT_ENOUGH_VALUES THEN DBMS_OUTPUT.PUT_LINE('No Enough Values ... '); END; It is still showing error message after specified it in EXCEPTION block. Can i handle these type of errors using PRAGMA EXCEPTION_INIT i.e not providing enough values in the select statement... If not what type of errors can be handled in System Defined Unnamed Exception using PRAGMA EXCEPTION_INIT.

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  • How to combine a list of choices to determine which select statement

    - by Larry
    I have a mysql db and am using php 5.2 What I am trying to do is offer a list of options for a person to select (only 1). The chosen option will cause a select, update, or delete statement to be ran. The results of the statement do not need to be shown, although, showing the old and then the new would be nice (no problems with that part tho'.). Pseudo-Code: Assign $choice = 0 Check the value of $choice // This way, if it = 100, we do a break Select a Choice:<br> 1. Adjust Status Value (+60) // $choice = 1<br> 2. Show all Ships <br> // $choice = 2 3. Show Ships in Port <br> // $choice = 3 ... 0. $choice="100" // if the value =100, quit this part Use either case (switch) or if/else statements to run the users choice1 If the choice is 1, then run the "Select" statement with the variable of $sql1 -- "SELECT .... If the choice is 2, then run the "Select" statement with the variable of $sql2 --- SELECT * FROM Ships If the choice is 3, then run the "Select" statement with the variable of $sql3 <br> .... If the choice is 0, then we are done. I figured the (3) statements would be assigned in php as: $sql1="...". $sql2="SELECT * FROM Ships" $sql3="SELECT * FROM Ships WHERE nPort="1" My idea was to use the switch statement, but got lost on it. :( I would like the options to be available over and over again, until a variable ($choice) is selected. In which case, this particular page is done and goes back to the "Main Menu"? The coding and display, if I use it, I can do. Just not sure how to write the way to select which one I want. It is possible that I would run all of the queries, and other times, only one, so that is why I would like the choice. An area I get confused in is the proper forms to use such as -- ' ' " " and ...?? Not sure the # of options I will end up with, but it will be more than 5 but less than 20 / page. So if I get the system down for 2-3 choices, I can replicate it for as many as I may need. And, as always, if a better way exists, I am willing to try it. Thanks again... Larry

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  • Linq issue retrieving single value from mssql

    - by Anicho
    Hey Guys, having an issue with linq, I am basically doing the following but it is saying it is "UserProfile does not contain definition for Username" in the current context where I wrote "u.Username" but it does exist I have added UserProfile table to MyDbml.dbml and if I connect to another table it works fine. TiamoDataContext context = new TiamoDataContext(); var user = (from u in context.UserProfiles where u.Username == UsernameLabel select u).FirstOrDefault(); I am flustered by what small detail I have missed out to get this to work, anyone have any clues it would be much appreciation.

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  • How can I format Custom Data and display in autocomplete when source is an DB

    - by Andres Scarpone
    so I'm trying to get some info in the auto-complete widget like it's shown in the JQuery UI demo Demo, the only problem is they use a variable that they fill with the data they want to show, I instead want to access the data and the different description and stuff using a Data Base in MySQL, for this I have changed the source to use another php page that looks up the info. here is the code for the Auto-complete, I really don't understand the methods so I haven't changed it from the basic search. This is the JS: $(document).ready((function(){ $( "#completa" ).autocomplete({ source: "buscar.php", minLength: 1, focus: function (event, ui){ $("#completa").val(ui.item.val); return false; }; })); This is what I have in buscar.php: <?php $conec = mysql_connect(localhost, root, admin); if(!$conec) { die(mysql_error()); } else { $bd = mysql_select_db("ve_test",$conec ); if(!$bd) { die(mysql_error()); } } $termino = trim(strip_tags($_GET['term']));//Obtener el termino que envia el autocompletar $qstring = "SELECT name, descripcion FROM VE_table WHERE name LIKE '%".$termino."%'"; $result = mysql_query($qstring);//Solicitud a la Base de Datos while ($row = mysql_fetch_array($result,MYSQL_ASSOC))//Realizar un LOOP sobre los valores obtenidos { $row['value']=htmlentities(stripslashes($row['name'])); $row_set[] = $row;//build an array } echo json_encode($row_set);//Enviar los datos al autocompletar en codificacion JSON, Altamente Necesario. ?

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  • Linq Distinct() by name for populate a dropdown list with name and value

    - by AndreMiranda
    I'm trying to populate a Drop down list with pharmaceutical companies, like Bayer, Medley etc. And, I'm getting theses names from DB and theses names are repeated in DB, but with different id's. I'm trying to use Linq Distinct(), but I don't want to use the equality comparer. Is there another way? My drop down list must be filled with the id and the name of the company. I'm trying something like: var x = _partnerService .SelectPartners() .Select(c => new {codPartner = c.codPartner, name = c.name}) .Distinct(); This is showing repeated companies in ddl. thanks!

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  • SqlCE DB occasionally freezes on one handheld, not another

    - by Michael
    I have two types of custom handhelds which are similar, but slightly different, each running the same WinForm application and a WinCE database: Type 1: WinCE 4.2, 400 mhz, 93244 kb Type 2: WinCE 5.0, 520 mhz, 84208 kb Type 1 will happily proceed through a large batch db operation (initiated) by the app, by Type 2 will consistently begin c-r-a-w-l-i-n-g (for several to many cycles) at around the 200 cycle mark. As several points it will begin running normally and then crawl again. The app does several db op's (inserts, updates and selects, no deletes). To simplify my situation, I've built a small test app which essentially does this: command_s.CommandText = "select dvr from vr where vid = 2211250"; command_u.CommandText = "update pvr set LocationID=81 where Status='OK' and vri = 27861"; while(going) { command_s.ExecuteScalar(); command_u.ExecuteNonQuery(); } and set it off running on the two units side by side. Sure enough, the slower (400 mhz) unit is outpacing the faster (520 mhz) unit (it's about 5000 cycles ahead right now) and I can see noticable pauses on the 520 mhz unit. What is causing this?

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  • count(*) is it really expensive ?

    - by Anil Namde
    I have a page where i have 4 tabs displaying 4 different reports based of different tables. Now i get row count of each tabled using select count() from table query and display number of rows available in each table on the tabs. Now with each page post back 5 count() queries are executed (4 to get counts and 1 for pagination) and 1 query for getting report. Now my question is should is count(*) query really expensive that i should keep the row counts (at least which are displayed on tab) in view state of page instead of queering each time? How much expensive it is ?

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  • HTML5 Web Database Security

    - by Daniel Dimovski
    Should the HTML5 database be used to store any form of private information? Say we have the following scenario; You're browsing a web-mail client, that uses the web database to store mail drafts after you've written some information you close the web browser. What's to stop me from getting access to this information? If the webpage tries to clean out old information when opened a user-script could easily prevent the website from fully loading and then search through the database. Furthermore the names of databases and tables are easily available through the web-mail client's source. W3C Draft

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