Search Results

Search found 40744 results on 1630 pages for 'sql interview questions a'.

Page 693/1630 | < Previous Page | 689 690 691 692 693 694 695 696 697 698 699 700  | Next Page >

  • Does normalization really hurt performance in high traffic sites?

    - by Luke101
    I am designing a database and I would like to normalize the database. I one query I will joining about 30-40 tables. Will this hurt the website performance if it ever becomes extremely popular? This will be the main query and it will be getting called 50% of the time. The other queries I will be joining about 2 tables. I have a choice right now to normalize or not to normalize but if the normalization becomes a problem in the future i may have to rewrite 40% of the software and it may take me a long time. Does normalization really hurt in this case? Should I denormalize now while I have the time?

    Read the article

  • Select 2 Rows from Table when COUNT of another table

    - by Marcus
    Here is the code that I currently have: SELECT `A`.* FROM `A` LEFT JOIN `B` ON `A`.`A_id` = `B`.`value_1` WHERE `B`.`value_2` IS NULL AND `B`.`userid` IS NULL ORDER BY RAND() LIMIT 2 What it currently is supposed to do is select 2 rows from A when the 2 rows A_id being selected are not in value_1 or value_2 in B. And the rows in B are specific to individual users with userid. What I need to do is make it also so that also checks if there are already N rows in B matching a A_id (either in value_1, or value_2) and userid, and if there are more than N rows, it doesn't select the A row.

    Read the article

  • Export MySQL Data as Insert Statements

    - by gav
    Hi All, I'm working in Ubuntu with MySql and I also have Query Browser and Administrator installed, I'm not afraid of the command line either if it helps. I want simply to be able to run a query and see a result set but then convert that result set into a series of commands that could be used to create the same rows in a table of an identical schema. I hope the question makes sense, it's quite a simple problem and one that must have been solved but I can't for the life of me work out where this kind of conversion is made available. Thanks in advance, Gav

    Read the article

  • Removal of table primary key in MySQL

    - by marionmaiden
    Hello, I've removed the primary key of one table of my MySQL database, but now, when I use the MySQL Administrator and try to edit some data of this table, it doesn't allow me to do this. The button edit that appears in the bottom of the table keeps visible, but disabled to click.

    Read the article

  • Service Broker not working after database restore

    - by roryok
    Have a working Service Broker set up on a server, we're in the process of moving to a new server but I can't seem to get Service Broker set up on the new box. Have done the obvious (to me) things like Enabling Broker on the DB, dropping the route, services, contract, queues and even message type and re adding them, setting ALTER QUEUE with STATUS ON SELECT * FROM sys.service_queues gives me a list of the queues, including my own two, which show as activation_enabled, receive_enabled etc. Needless to say the queues aren't working. When I drop messages into them nothing goes in and nothing comes out. Any ideas? I'm sure there's something really obvious I've missed...

    Read the article

  • kohana quotes in query.

    - by peter
    hey, i want to format a date in mysql using DATE_FORMAT(tblnews.datead, '%M %e, %Y, %l:%i%p') i cant seem to get the quotes right , so i keep getting errors. how would you put this in a query?

    Read the article

  • Filling a LOV in Oracle Apex based on data in another text box

    - by Martin Pugh
    I am fairly new to Oracle Apex, and have a problem. Our application currently has a method of entering data, with several text boxes and Optional List of Values. I would like to have an LOV based on information in another text box like so: select APPOINTMENT_ID PATIENT_ID from APPOINTMENT where PATIENT_ID = :P9_PAT_NUM where P9_PAT_NUM is a patient number in a text box. However, this would apparently only work if the text box has already been submitted, else it assumes the text box is null. Is there any way to get this working with an LOV, or perhaps some other method?

    Read the article

  • how to save html to a database field

    - by ooo
    i have an tiny editor web page where my users can use this editor and i am saving the html into my database. i am having issues saving this html to my database. for example if there is a name with a "'" or if there are other html character "<,","" etc, my code seems to blow up on the insert. Is there any best practices about taking any arbitrary html and have it persist fully to a db field without worrying about any specific characters.

    Read the article

  • Check for active connection in NHibernate

    - by Dofs
    I have a system with a few different databases, and I would like to check if a certain database is down, and if so display a message to the user. Is it possible in NHibernate to check if there is an active connection to the database, without having to request data and then catch the exception?

    Read the article

  • update query with join on two tables

    - by dba_query
    I have customer and address tables. query: select * from addresses a, customers b where a.id = b.id returns 474 records For these records, I'd like to add the id of customer table into cid of address table. Example: If for the first record the id of customer is 9 and id of address is also 9 then i'd like to insert 9 into cid column of address table. I tried: update addresses a, customers b set a.cid = b.id where a.id = b.id but this does not seem to work.

    Read the article

  • join select from multiple row values?

    - by user1869132
    Two tables 1) product -------------------- id | Name | price 1 | p1 | 10 2 | p2 | 20 3 | p3 | 30 2) product_attributes: --------------------------------------------------- id | product_id | attribute_name | attribute_value --------------------------------------------------- 1 | 1 | size | 10 2 | 1 | colour | red 3 | 2 | size | 20 I need to join these two tables. In the where clause I need to match both the two rows attribute values. Is it possible to get the result based on two rows value. Here if size=10 and colour=red. Output should be 1 | p1 | 10 It could be greatly helpful to get a query for this.

    Read the article

  • Would you make this method Static or not?

    - by Adam Drummond
    During a code review I presented a method quickly to the team that I had made static and one person agreed that there was no reason for it to not be static and a person disagreed saying that he would not make it static because it wasn't necessary and just to be on the safe side for future modifications and testing. So I did quite a bit of research and obviously it's a specialized case but I would like to know what you would do in this situation and why? (Its basically a helper method I call from a few different methods, a very low traffic page. More for my knowledge and learning on Static.) private IEnumerable<Category> GetCategoryByID(int id, Context context) { var categoryQuery = from selectAllProc in context.SelectAll_sp() where selectAllProc.CategoryID == id select selectAllProc; return categoryQuery; }

    Read the article

  • Indexing affects only the WHERE clause?

    - by andre matos
    If I have something like: CREATE INDEX idx_myTable_field_x ON myTable USING btree (field_x); SELECT COUNT(field_x), field_x FROM myTable GROUP BY field_x ORDER BY field_x; Imagine myTable with around 500,000 rows and most of field_x values being unique. Since I don't use any WHERE clause, will the created index have any effect at all in my query? Edit: I'm asking this question because I don't get any relevant difference between query-times before and after creating the index; They always take about 8 seconds (which, of course is too much time!). Is this behaviour expected?

    Read the article

  • MySQL left outer join is slow

    - by Ryan Doherty
    Hi, hoping to get some help with this query, I've worked at it for a while now and can't get it any faster: SELECT date, count(id) as 'visits' FROM dates LEFT OUTER JOIN visits ON (dates.date = DATE(visits.start) and account_id = 40 ) WHERE date >= '2010-12-13' AND date <= '2011-1-13' GROUP BY date ORDER BY date ASC That query takes about 8 seconds to run. I've added indexes on dates.date, visits.start, visits.account_id and visits.start+visits.account_id and can't get it to run any faster. Table structure (only showing relevant columns in visit table): create table visits ( `id` int(11) NOT NULL AUTO_INCREMENT, `account_id` int(11) NOT NULL, `start` DATETIME NOT NULL, `end` DATETIME NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; CREATE TABLE `dates` ( `date` date NOT NULL, PRIMARY KEY (`date`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; dates table contains all days from 2010-1-1 to 2020-1-1 (~3k rows). visits table contains about 400k rows dating from 2010-6-1 to yesterday. I'm using the date table so the join will return 0 visits for days there were no visits. Results I want for reference: +------------+--------+ | date | visits | +------------+--------+ | 2010-12-13 | 301 | | 2010-12-14 | 356 | | 2010-12-15 | 423 | | 2010-12-16 | 332 | | 2010-12-17 | 346 | | 2010-12-18 | 226 | | 2010-12-19 | 213 | | 2010-12-20 | 311 | | 2010-12-21 | 273 | | 2010-12-22 | 286 | | 2010-12-23 | 241 | | 2010-12-24 | 149 | | 2010-12-25 | 102 | | 2010-12-26 | 174 | | 2010-12-27 | 258 | | 2010-12-28 | 348 | | 2010-12-29 | 392 | | 2010-12-30 | 395 | | 2010-12-31 | 278 | | 2011-01-01 | 241 | | 2011-01-02 | 295 | | 2011-01-03 | 369 | | 2011-01-04 | 438 | | 2011-01-05 | 393 | | 2011-01-06 | 368 | | 2011-01-07 | 435 | | 2011-01-08 | 313 | | 2011-01-09 | 250 | | 2011-01-10 | 345 | | 2011-01-11 | 387 | | 2011-01-12 | 0 | | 2011-01-13 | 0 | +------------+--------+ Thanks in advance for any help!

    Read the article

  • Get DTS Step Description from TSQL?

    - by vikasde
    I am trying to get the DTS Step Name/Description of a given DTS Package in SQL2000. I am not able to see anything in the msdb database. I can see the initial DTS name, however I dont see anything to get the details. Anybody knows where this info is stored?

    Read the article

  • Sybase ASA 8.0 trigger how to determine whether to insert ,update,delete operate.

    - by guaike
    Follow is my trigger of Sybase ASA 8.0 script: Create trigger dba.test after insert,delete,update order 1 on DBA.tb_press referencing old as _old new as _new for each row begin --How to detect deleteOperate,updateOperate? if deleteOperate then insert into syncLog(tableName,keyId,version,operate) select tb_press,_old.id,1,'delete' end if; end how to determine whether to insert ,update,delete operate.

    Read the article

  • SQL query INSERT not working inserting values into my DB.

    - by Aiden Ryan
    Hello, I'm trying to insert registration data into a database but my php code isn't inserting the values into the DB although I'm not getting any errors either, can someone help me? this is the code i'm currently using: $connect = mysql_connect("localhost","myusername","mypassword"); mysql_select_db("application"); $queryreg = mysql_query('INSERT INTO users("username","password","email","date") VALUES("$username","$password","$email","$date")'); die ("You Have Been Registered."); I just need to add the username password email and date into the fields i have specified but it won't work, please someone help!

    Read the article

  • Using stored procedures to generate RDLC report in C#

    - by NDraskovic
    I'm making an application that generates reports for my client. I'm using his database that contains stored procedures which return the data needed for the reports. The problem is that I don't know how to execute them from the application (more specific the TableAdapter in my dataset). When I use the visual aid to create the TableAdapter, it shows the error "Invalid object named #table1". This is weird because there is a temporary table called #table1 in the stored procedure. When I try to do the whole job programmatically, I get the exception Incorrect syntax near '.'. An object or column name is missing or empty. For SELECT INTO statements, verify each column has a name. For other statements, look for empty alias names. Aliases defined as "" or [] are not allowed. Change the alias to a valid name. I created a DataTable that has identical structure as the result of the stored procedure, but I still get the same exception

    Read the article

  • How to do this query?

    - by Damiano
    Hello everybody! I have a mysql table with these columns: ID (auto-increment) ID_BOOK (int) PRICE (double) DATA (date) I know two ID_BOOK values, example, 1 and 2. QUERY: I have to extract all the PRICE (of the ID_BOOK=1 and ID_BOOK=2) where DATA is the same! Table example: 1 1 10.00 2010-05-16 2 1 11.00 2010-05-15 3 1 12.00 2010-05-14 4 2 18.00 2010-05-16 5 2 11.50 2010-05-15 Result example: 1 1 10.00 2010-05-16 4 2 18.00 2010-05-16 2 1 11.00 2010-05-15 5 2 11.50 2010-05-15 ID_BOOK=2 hasn't 2010-05-14 so i jump it. Thank you so much!

    Read the article

< Previous Page | 689 690 691 692 693 694 695 696 697 698 699 700  | Next Page >