sql training - Page 616

Facebook database design?

- by Marin

I have always wondered how Facebook designed the friend <- user relation. I figure the user table is something like this: user_email PK user_id PK password I figure the table with user's data (sex, age etc connected via user email I would assume). How does it connect all the friends to this user? Something like this? user_id friend_id_1 friend_id_2 friend_id_3 friend_id_N Probably not. Because the number of users is unknown and will expand.

Read the article

Help on understanding multiple columns on an index?

- by Xaisoft

Assume I have a table called "table" and I have 3 columns, a, b, and c. What does it mean to have a non-clustered index on columns a,b? Is a nonclustered index on columns a,b the same as a nonclustered index on columns b,a? (Note the order). Also, Is a nonclustered index on column a the same as a nonclustered index on a,c? I was looking at the website sqlserver performance and they had these dmv scripts where it would tell you if you had overlapping indexes and I believe it was saying that having an index on a is the same as a,b, so it is redundant. Is this true about indexes? One last question is why is the clustered index put on the primary key. Most of the time the primary key is not queried against, so shouldn't the clustered index be on the most queried column. I am probably missing something here like having it on the primary key speeds up joins? Great explanations. Should I turn this into a wiki and change the title index explanation?

Read the article

Can't find which row is causing conversion error

- by Marwan

I have the following table: CREATE TABLE [dbo].[Accounts1]( [AccountId] [nvarchar](50) NULL, [ExpiryDate] [nvarchar](50) NULL ) I am trying to convert nvarchar to datetime using this query: select convert(datetime, expirydate) from accounts I get this error: Conversion failed when converting datetime from character string. The status bar says "2390 rows". I go to rows 2390, 2391 and 2392. There is nothing wrong with the data there. I even try to convert those particular rows and it works. How can I find out which row(s) is causing the conversion error?

Read the article

ORA-01722: invalid number

- by Lluis Martinez

I'm getting the infamous invalid number Oracle error. Hibernate is issuing an INSERT with a lot of columns, I want to know just the name of the column giving the problem. Is it possible? I hate Oracle messages, in 15 years they haven't improved a bit (the reason why is beyond my imagination). FYI the insert is this: insert into GEM_INVOICE_HEADER (ENDORSEE_ACCOUNT_ID, INVOICE_CODE, APPROVAL_ORGAN, APROVAL_DATE, APROVAL_REFERENCE, BALANCE_BASE_AMOUNT, BALANCE_DEDUCT_AMOUNT, BALANCE_TOTAL_AMOUNT, BALANCE_VAT_AMOUNT, BALANCE_VAT_DED_AMOUNT, BALANCE_VAT_NOT_DED_AMOUNT, DESCRIPTION, SUPPLIER_INVOICE_NUMBER, INVOICE_DATE, RECEIPT_DATE, MEMO, VAT_INTRACOM, INVOICE_BASE_AMOUNT, INVOICE_VAT_AMOUNT, INVOICE_VAT_DED_AMOUNT, INVOICE_VAT_NOT_DED_AMOUNT, INVOICE_DEDUCT_AMOUNT, INVOICE_TOTAL_AMOUNT, VAT_EXEMPT, RECTIFICATION_SIGN, REASON, LOT, FILE_ID, RETAINED, INSTITUTION_ID, PERIOD_CODE, IS_RECTIFIED, DEFAULT_OFFBUDGET_ACCOUNT, OFFBUDGET_DOC_ID, PHASE_OF_ACCOUNTING, ACCOUNTED_OFF_BUDGET, CANCEL_DOC_ID, BUDGET_TYPE, INVOICE_TYPE, SOURCE_ID, STATE_ID, MANAGER_UNIT_ID, DOCUMENT_TYPE_CODE, ACCOUNTED_DOC_ID, ACCOUNTING_LIST, ENDORSEE_ID, PAYMASTER_ID, SUPPLIER_ID, SUPPLIER_ACCOUNT_ID, PAY_JUSTIFY_ID, PETTY_CASH_ID, DBOID) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)

Read the article

"Attach or Add an entity that is not new...loaded from another DataContext. This is not supported."

- by sah302

Similar error as other questions, but not quite the same, I am not trying to attach anything. What I am trying to do is insert a new row into a linking table, specifically UserAccomplishment. Relations are set in LINQ to User and Accomplishment Tables. I have a generic insert function: Public Function insertRow(ByVal entity As ImplementationType) As Boolean If entity IsNot Nothing Then Dim lcfdatacontext As New LCFDataContext() Try lcfdatacontext.GetTable(Of ImplementationType)().InsertOnSubmit(entity) lcfdatacontext.SubmitChanges() lcfdatacontext.Dispose() Return True Catch ex As Exception Return False End Try Else Return False End If End Function If you try and give UserAccomplishment the two appropriate objects this will naturally crap out if either the User or Accomplishment already exist. It only works when both user and accomplishment don't exist. I expected this behavior. What does work is simply giving the userAccomplishment object a user.id and accomplishment.id and populating the rest of the fields. This works but is kind of awkward to use in my app, it would be much easier to simply pass in both objects and have it work out what already exists and what doesn't. Okay so I made the following (please ignore the fact that this is horribly inefficient because I know it is): Public Class UserAccomplishmentDao Inherits EntityDao(Of UserAccomplishment) Public Function insertLinkerObjectRow(ByVal userAccomplishment As UserAccomplishment) Dim insertSuccess As Boolean = False If Not userAccomplishment Is Nothing Then Dim userDao As New UserDao() Dim accomplishmentDao As New AccomplishmentDao() Dim user As New User() Dim accomplishment As New Accomplishment() 'see if either object already exists in db' user = userDao.getOneByValueOfProperty("Id", userAccomplishment.User.Id) accomplishment = accomplishmentDao.getOneByValueOfProperty("Id", userAccomplishment.Accomplishment.Id) If user Is Nothing And accomplishment Is Nothing Then 'neither the user or the accomplishment exist, both are new so insert them both, typical insert' insertSuccess = Me.insertRow(userAccomplishment) ElseIf user Is Nothing And Not accomplishment Is Nothing Then 'user is new, accomplishment is not new, so just insert the user, and the relation in userAccomplishment' Dim userWithExistingAccomplishment As New UserAccomplishment(userAccomplishment.User, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userWithExistingAccomplishment) ElseIf Not user Is Nothing And accomplishment Is Nothing Then 'user is not new, accomplishment is new, so just insert the accomplishment, and the relation in userAccomplishment' Dim existingUserWithAccomplishment As New UserAccomplishment(userAccomplishment.UserId, userAccomplishment.Accomplishment, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(existingUserWithAccomplishment) Else 'both are not new, just add the relation' Dim userAccomplishmentBothExist As New UserAccomplishment(userAccomplishment.User.Id, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userAccomplishmentBothExist) End If End If Return insertSuccess End Function End Class Alright, here I basically check if the supplied user and accomplishment already exists in the db, and if so call an appropriate constructor that will leave whatever already exists empty, but supply the rest of the information so the insert can succeed. However, upon trying an insert: Dim result As Boolean = Me.userAccomplishmentDao.insertLinkerObjectRow(userAccomplishment) In which the user already exists, but the accomplishment does not (the 99% typical scenario) I get the error: "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." I have debugged this multiple times now and am not sure why this is occuring, if either User or Accomplishment exist, I am not including it in the final object to try to insert. So nothing appears to be attempted to be added. Even in debug, upon insert, the object was set to empty. So the accomplishment is new and the user is empty. 1) Why is it still saying that and how can I fix it ..using my current structure 2) Pre-emptive 'use repository pattern answers' - I know this way kind of sucks in general and I should be using the repository pattern. However, I can't use that in the current project because I don't have time to refactor that due to my non existence knowledge of it and time constraints. The usage of the app is going to so small that the inefficient use of datacontext's and what have you won't matter so much. I can refactor it once it's up and running, but for now I just need to 'push through' with my current structure. Edit: I also just tested this when having both already exists, and only insert each object's IDs into the table, that works. So I guess I could manually insert whichever object doesn't exist as a single insert, then put the ids only into the linking table, but I still don't know why when one object exists, and I make it empty, it doens't work.

Read the article

Adding rows with linq trouble with reference table

- by Laurence Burke

I am adding a new address and I know the structure as AddressID = PK and all other entities are non nullable. Now on insert of a new row the addrID Pk is autogened and I am wondering if I would have to get that to create a new row in the referencing table EmployeeAddress or does that automatically get generated also. also I want to be able to repopulate the dropdownlist that lists the current employee's addresses with the newly created address. static uint _curEmpID; protected void btnAdd_Click(object sender, EventArgs e) { if (txtZip.Text != "" && txtAdd1.Text != "" && txtCity.Text != "") { TestDataClassDataContext dc = new TestDataClassDataContext(); Address addr = new Address() { AddressLine1 = txtAdd1.Text, AddressLine2 = txtAdd2.Text, City = txtCity.Text, PostalCode = txtZip.Text, StateProvinceID = Convert.ToInt32(ddlState.SelectedValue) }; dc.Addresses.InsertOnSubmit(addr); lblSuccess.Visible = true; lblErrMsg.Visible = false; dc.SubmitChanges(); // // TODO: insert new row in EmployeeAddress to reference CurEmp to newly created address // SetAddrList(); } else { lblErrMsg.Text = "Invalid Input"; lblErrMsg.Visible = true; } } protected void ddlAddList_SelectedIndexChanged(object sender, EventArgs e) { lblErrMsg.Visible = false; lblSuccess.Visible = false; TestDataClassDataContext dc = new TestDataClassDataContext(); dc.ObjectTrackingEnabled = false; if (ddlAddList.SelectedValue != "-1") { var addr = (from a in dc.Addresses where a.AddressID == Convert.ToInt32(ddlAddList.SelectedValue) select a).FirstOrDefault(); txtAdd1.Text = addr.AddressLine1; txtAdd2.Text = addr.AddressLine2; txtCity.Text = addr.City; txtZip.Text = addr.PostalCode; ddlState.SelectedValue = addr.StateProvinceID.ToString(); btnSubmit.Visible = true; btnAdd.Visible = false; } else { txtAdd1.Text = ""; txtAdd2.Text = ""; txtCity.Text = ""; txtZip.Text = ""; btnAdd.Visible = true; btnSubmit.Visible = false; } } protected void SetAddrList() { TestDataClassDataContext dc = new TestDataClassDataContext(); dc.ObjectTrackingEnabled = false; var addList = from addr in dc.Addresses from eaddr in dc.EmployeeAddresses where eaddr.EmployeeID == _curEmpID && addr.AddressID == eaddr.AddressID select new { AddValue = addr.AddressID, AddText = addr.AddressID, }; ddlAddList.DataSource = addList; ddlAddList.DataValueField = "AddValue"; ddlAddList.DataTextField = "AddText"; ddlAddList.DataBind(); ddlAddList.Items.Add(new ListItem("<Add Address>", "-1")); } OK I am hoping that I did not include too much code. I would really appreciate any other comments about I could otherwise improve this code in any other ways also.

Read the article

Full Text Search in MSSQL2008 shows wrong display_item for Thai language

- by ensecoz

I am working with MSSQL2008. My task is to investigate the issue where FTS cannot find the right result for Thai. First, I have the table which enables the FTS on the column 'ItemName' which is nvarchar. The Catalog is created with the Thai Language. Note that the Thai language is one of the languages that doesn't separate the word by spaces, so '????' '???' '????' are written like this in a sentence: '???????????' In the table, there are many rows that include the word (????); for example row#1 (ItemName: '???????????') On the webpage, I try to search for '????' but SQLServer cannot find it. So I try to investigate it by trying the following query in SQLServer: select * from sys.dm_fts_parser(N'"???????????"', 1054, 0, 0) ...to see how the words are broken. The first one is the text to be broken. The second parameter is to specify that we're using Thai (WorkBreaker, so on). Here is the result: row#1 (display_item: '????', source_item: '???????????') row#2 (display_item: '????', source_item: '???????????') row#3 (display_item: '??', source_item: '???????????') Notice that the first and second row display the wrong display_item '?' in the '????' isn't even Thai characters. '?' in '????' is not a Thai character either. So the question is where did those alien characters come from? I guess this why I cannot search for '????' because the word breaker is broken and keeping the wrong character in the indexes. Please help!

Read the article

What are the disadvantages of VistaDB

- by PhantomTypist

I am looking into using a lightweight serverless database engine like SQLite, Firebird, or VistaDB in an upcoming project. Someone asked about What are the advantages of VistaDB. I would like to know what are the disadvantages of using VistaDB versus other technology?

Read the article

Insert Data from to a table

- by Lee_McIntosh

I have a table that lists number of comments from a particular site like the following: Date Site Comments Total --------------------------------------------------------------- 2010-04-01 00:00:00.000 1 5 5 2010-04-01 00:00:00.000 2 8 13 2010-04-01 00:00:00.000 4 2 7 2010-04-01 00:00:00.000 7 13 13 2010-04-01 00:00:00.000 9 1 2 I have another table that lists ALL sites for example from 1 to 10 Site ----- 1 2 ... 9 10 Using the following code i can find out which sites are missing entries for the previous month: SELECT s.site from tbl_Sites s EXCEPT SELECT c.site from tbl_Comments c WHERE c.[Date] = DATEADD(mm, DATEDIFF(mm, 0, GetDate()) -1,0) Producing: site ----- 3 5 6 8 10 I would like to be able to insert the missing sites that is listed from my query into the comments table with some default values, i.e '0's Date Site Comments Total --------------------------------------------------------------- 2010-04-01 00:00:00.000 3 0 0 2010-04-01 00:00:00.000 5 0 0 2010-04-01 00:00:00.000 6 0 0 2010-04-01 00:00:00.000 8 0 0 2010-04-01 00:00:00.000 10 0 0 the question is, how did i update/insert the table/values? cheers, Lee

Read the article

tsql : how to do a substring replace?

- by phill

goal: I have the string "1234432144" I want to only replace the first 2 4's with '10' so I would get '1231032144' Is there a way to do this in tsql? so far I have come up with the tsql substring() function substring('1234432144', 4, 2) which draws the 44 .. however how do i replace it within the existing string? If i wrap a replace function around it, it replaces all occurrences of 44 in the string. any ideas? thanks in advance.

Read the article

How do views reduce code duplication?

- by Debuger

Hi! I read something like this about db views: Views are incredibly powerful and useful for one reason that stands out above all the other very good reasons. They reduce code duplication. That is, in most cases, the bottom line. If a query will be used in three or more places, then a view will drastically simplify your changes if the schema or query parameters change. I once had to edit 22 stored procedures to change some query logic. If the original architecture had utilized views, then I would have had only three changes. Can anyone explain to me how it works, and maybe give me some examples? Best regards!

Read the article

comparing data via a function

- by tigermain

I have two sets of data (locations) in seperate tables and I need to compare if they match or not. I have a UDF which performs a calculation based upon 5 values from each table. How do I perform a select with a join using this udf? my udf is basically defined by.... ALTER FUNCTION [dbo].[MatchRanking] ( @Latitude FLOAT , @Longitude FLOAT , @Postcode VARCHAR(16) , @CompanyName VARCHAR(256) , @TelephoneNumber VARCHAR(32) , @Latitude2 FLOAT , @Longitude2 FLOAT , @Postcode2 VARCHAR(16) , @CompanyName2 VARCHAR(256) , @TelephoneNumber2 VARCHAR(32) ) RETURNS INT

Read the article

mysql result set joining existing table

- by Yang

is there any way to avoid using tmp table? I am using a query with aggregate function (sum) to generate the sum of each product: the result looks like this: product_name | sum(qty) product_1 | 100 product_2 | 200 product_5 | 300 now i want to join the above result to another table called products. so that i will have a summary like this: product_name | sum(qty) product_1 | 100 product_2 | 200 product_3 | 0 product_4 | 0 product_5 | 300 i know 1 way of doing this is the dump the 1st query result to a temp table then join it with products table. is there a better way?

Read the article

Diaplaying SSMS standard report in your web application

- by Rajganesh Mountbatton

SSMS 2005 & 2008 comes with inbuilt standard reports. How can we display these standard reports inside a asp.net web site?

Read the article

To log in stored procedures?

- by hgulyan

If you have a long running SP, do you log somehow it's actions or just wait for this message? "Command(s) completed successfully." I assume, that there can be plenty solutions on this subject, but is there any best practice - a simple solution that is frequently used?

Read the article

php using wamp server start up error

- by mathirengasamy

i try to install moodle web software...i m using wamp server and sqlserver 2005 version. i install php driver for php5.3.0 thread safe version..i just paste that php_sqlsrv_ts.dll driver file into my php ext directory...i include this line extension=php_sqlsrv_ts.dll in my php.ini file... now i restart my wampserver...i m getting this error... PHP Startup: sqlsrv: Unable to initialize module Module compiled with module API=20060613 PHP compiled with module API=20090626 These options need to match get this error also in my apache log file ADODB Error: [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified please anybody help me..

Read the article

NHibernate - does it work well with database-level cascading deletions on foreign key constraints

- by Nelson LaQuet

Dose nHibernate play well with database level cascading deletions? What I mean is that if I have a constraint set at the RDBMS level to cascade delete all orphans, will nHibernate invoke any custom delete logic at the application level if I were to delete an entity though nHibernate? Or should I remove the cascading deletions from the RDBMS level and just use the cascading delete feature of nHibernate itself by defining that behavior though its configuration? Thanks

Read the article

same table, 1 field to 2 field query

- by edib

I have 2 tables: 1st holds employees (of ones in any position) and the 2nd holds manager employee relations with id numbers. I want to write a query like 1st field: name(employee), 2nd field: name(manager) How can I do that?

Read the article

It is possible to record a data that have a straight row in mysql based on date or sequence?

- by user1987816

Read the article

Mysql stored procedure where clause

- by Mneva skoko

I am having a problem with this stored procedure: Delimiter // Create procedure(in varchar(50)) Begin Select * from employees where email = eml; End// Delimiter ; I don't get errors when I run this procedure but when i call it in my php script it returns nothing.

Read the article

Is it possible to run an alter on all my database objects to test them

- by Khanzor

I'm in the course of doing some schema migrations, and would like to know if it's possible or advisable to run every stored procedure, view and function in my database as an alter statement to "compile" them all to make sure nothing is completely broken.

Read the article

How to efficiently SELECT rows from database table based on selected set of values

- by Chau Chee Yang

I have a transaction table of 1 million rows. The table has a field name "Code" to keep customer's ID. There are about 10,000 different customer code. I have an GUI interface allow user to render a report from transaction table. User may select arbitrary number of customers for rendering. I use IN operator first and it works for few customers: SELECT * FROM TRANS_TABLE WHERE CODE IN ('...', '...', '...') I quickly run into problem if I select few thousand customers. There is limitation using IN operator. An alternate way is create a temporary table with only one field of CODE, and inject selected customer codes into the temporary table using INSERT statement. I may then using SELECT A.* FROM TRANS_TABLE A INNER JOIN TEMP B ON (A.CODE=B.CODE) This works nice for huge selection. However, there is performance overhead for temporary table creation, INSERT injection and dropping of temporary table. Do you aware of better solution to handle this situation?

Read the article

Fetch posts with attachments in a certain category?

- by TiuTalk

I need to retreive a list of posts that have (at least) one attachment that belongs to a category in WordPress. The relation between attachments and categories I made by myself using the WordPress default method. Here's the query that i'm running right now: SELECT p.* FROM `wp_posts` AS p # The post INNER JOIN `wp_posts` AS a # The attachment ON p.`ID` = a.`post_parent` AND a.`post_type` = 'attachment' INNER JOIN `wp_term_relationships` AS ra ON a.`ID` = ra.`object_id` AND ra.`term_taxonomy_id` IN (3) # The category ID list WHERE p.`post_type` = 'post' ORDER BY p.`post_date` DESC LIMIT 15 The problem here is that the query only use the first found attachment, and if it doesn't belongs to the category, the result isn't returned.

Read the article

how to do complete multiple replaces throughout table in ms-access

- by silverkid

i am a little confused in finding out what would be the best way to replace all occurances of 1. Blanks 2. - 3. NA from all collumns of TableA with question mark ? charachter. Sample Row in orignal tableA 444586 RAUR <blank> 8 570 NA - 13 - SCHS299 MP 339 70 EN <blank> Same Row in Expected TableA 444586 RAUR ? 8 570 ? ? 13 ? SCHS299 MP 339 70 EN ? please help me out I cant use the Find Replace Toolbar of access.

Read the article

Building a subquery with ARel in Rails3

- by Christopher

I am trying to build this query in ARel: SELECT FLOOR(AVG(num)) FROM ( SELECT COUNT(attendees.id) AS num, meetings.club_id FROM `meetings` INNER JOIN `attendees` ON `attendees`.`meeting_id` = `meetings`.`id` WHERE (`meetings`.club_id = 1) GROUP BY meetings.id) tmp GROUP BY tmp.club_id It returns the average number of attendees per meeting, per club. (a club has many meetings and a meeting has many attendees) So far I have (declared in class Club < ActiveRecord::Base): num_attendees = meetings.select("COUNT(attendees.id) AS num").joins(:attendees).group('meetings.id') Arel::Table.new('tmp', self.class.arel_engine).from(num_attendees).project('FLOOR(AVG(num))').group('tmp.club_id').to_sql but, I am getting the error: undefined method `visit_ActiveRecord_Relation' for #<Arel::Visitors::MySQL:0x9b42180> The documentation for generating non trivial ARel queries is a bit hard to come by. I have been using http://rdoc.info/github/rails/arel/master/frames Am I approaching this incorrectly? Or am I a few methods away from a solution?

Search Results

Search found 28985 results on 1160 pages for 'sql training'.

Page 616/1160 | < Previous Page | 612 613 614 615 616 617 618 619 620 621 622 623 | Next Page >

- by Marin

- by Xaisoft

- by Marwan

- by Lluis Martinez

- by sah302

- by Laurence Burke

- by ensecoz

- by PhantomTypist

- by Lee_McIntosh

- by phill

- by Debuger

- by tigermain

- by Yang

- by Rajganesh Mountbatton

- by hgulyan

- by mathirengasamy

- by Nelson LaQuet

- by edib

- by user1987816

- by Mneva skoko

- by Khanzor

- by Chau Chee Yang

- by TiuTalk

- by silverkid

- by Christopher

< Previous Page | 612 613 614 615 616 617 618 619 620 621 622 623 | Next Page >