Concurrent Access - New Record, Primary Key Problem....
Jul 23, 2005
Can someone explain what happens when two users concurrently attempt to
create a new record in a table with an autonumber primary key? For example,
user 1 creates a new record and manipulates it within a transaction making
use (perhaps) of the @@IDENTITY value when creating other, related records.
Before this transaction is complete, user 2 creates a new record and does
the same thing. Presumably they will both have the same @@IDENTITY? If
this is the case, how is it possible to manage such a situation?
I've been asked to turn our single-user database system into a multi-usersystem. At present, each user has a copy of the MSDE on their desktopmachine and uses our program to access it. In future, we would like tocentralise our MSDE instance and allow multiple users to access it. Inorder to facilitate this, we are going to only allow one user write accessto the system at a time (I know, its a kludge, but the system was neverdesigned for multiple users in the first place).I have a single, simple question this being the case: can I update a single"read-only" bit field in a table of the database in order to flag to otherusers that the system is in read-only mode in a way that avoids concurrencyissues? ie. does an "UPDATE" query lock and unlock? ( I suspect the answeris yes! ). If anyone else has experience of these things, I would alsoappreciate some tips on how best to proceed.ThanksRobin
I have this .NET application that inserts lucky draw entries into SQL server. Each entry may have a range of values that the winning number will be drawn from. For example,
The winning number will be picked from [1, 20]. Given this scenario, what is the best design that can handle the concurrency issue? If two entries are input at the same time, how to make sure it won't have the same starting value? Anyway to lock a table when one is accessing, disallowing other to run select query?
Ok I know this might not be the most accurate place to post this but I know someone here has an answer for me on it.I need to get the product_ID of the new record that is created by this insert statement INSERTINTO products ( class_ID,category_ID,product_name,product_desc,product_image,product_dimension,product_o1,product_o2,product_o3,product_ac,product_ph,product_photo ) SELECT class_ID,category_ID,product_name,product_desc,product_image,product_dimension,product_o1,product_o2,product_o3,product_ac,product_ph,product_photo FROM productsWHERE product_ID = @productID
Hi I have a table in sql server with a numeric field as Primary Key. When i insert a new record i need that primary key increments automatic (like access auto increment) because i want avoid the possibility of duplicate Primary Keys. Is that possible? Thank you
I'm performing an insert on a table that has a relationship, but I also want to update the other table that has a foreign key relationship. How do I go about this? Thanks :)
Hi, Can someone please tell me the best practices for checking the primary key field before inserting a record into my database? As an example I have created an asp.net page using VB with an SQL server database. The web page will just insert two fields into a table (Name & Surname into the Names table). The primary key or the Names table is "Name". When I click the Submit button I would like to check to ensure there is not a duplicate primary key. If there is return a user friendly message i.e. A record already exisits, if there no duplicate, add the record. I guess I could use try, catch within the .APSX page or would a stored procedure be better? Thanks Brett
hii I have to insert some data into a table from the webpage. For that I need to know the last occurred value in the primary key and increment this by one and then insert the new record into the table. I am working with SQL Server 2005. I am coding in VB and ASP.NET 2.0. How will I go about this?? Is there some easy way for me to knw the last value of the primary key n then insert the record. It would be great if I get the idea more clear with the help of some code... Thanks
Please help me somebody solve my problem with my first :o trigger: ALTER TRIGGER partner_update ON dbo.partner FOR UPDATE AS INSERT INTO partner (name) SELECT name FROM deleted UPDATE invoice SET id_partner= *** WHERE id_partner = (SELECT id_partner FROM deleted) *** - here I want to add a "reference" to the newly added record's automatically generated primary key (not to the updated!) Is it possible?
I'm using a Merge statement to update/insert values into a table. The Source is not a table, but the parameters from a Powershell script. I am not using the Primary Key to match on, but rather the Computer Name (FullComputerName).
I am looking on how-to return the Primary Key (ComputerPKID) of an updated record as "chained" scripts will require a Primary Key, new or used.As an aside: the code below does return the newly generated Primary Key of an Inserted record.
We have a large table which is very old and not much ppl take care about, recently there is a performance problem from the report need to query to this table. Eventally we find that this table have primary key missing and there is duplicate data which make "alter table add primary key" don't work
Besides the data size of this table require unacceptable time to execute something like "insert into new_table_with_pk from select distinct * from old table"
Do you have any recommendation of fixing this? As the application run on oracle , sybase and sql server, is that cross database approace will work?
I have an SQL database which I need to export into Access, I know how to this however the Primary Key's does not transfer over and more importantly once exported I cannot set the primary key to auto number as their is already information in the table.
I know I can just set up the table, with a primary key set to an autonumber and import the other fields but as the primary key's are foreign keys in other tables I need the rows in the access table to have the same ID number as in the SQL database.
Hope the above makes sense to someone and any help would be greatly appreciated.
I have been pulling my hair trying to figure out what the guys at microsoft were thinking when creating the ADOX library. I have an access table that is syncronized with a SQL server. The table has a primary key with two columns [User] and [Program]. The SQL Server has both columns in as the primary key columns and I have a syncronization mechanism that is responsible for several things, one of which is to recreate the Access data structure. All works well for all tables except this one. I have tried to create the multi-column key in several ways, none that worked. Let me show you what I am doing:
a while back i had to do a project with an access database, one of the biggest problems i had back then was gettting the primary key of a datarow you had just inserted into the database.
After a long set of trial and error i came up with the following:
- add the tablemappings of a table - call the dataadapte.fillschema method
then after inserting a new row into the database the primary key gets filled in automatically!
now thing is
i was hoping to duplicate this in sql server
but it doesn't seem to work at all
so after i insert a row into my datatable and update it the row is in the database but in vb the datarow primary key is not filled in! anyone have an idea?
prefereabely one that does not resort to stored procedures with return parameters etc
I have an Access db that has a linked table to a sql table. The sql table has a UniqueIdentifier field in it. How do I create a new record through access in that table and have the UNIQUEIDENTIFIER autogenerated?
Previously same records exists in table having primary key and table having foreign key . we have faced 7 records were lost from primary key table but same record exists in foreign key table.
I am using the following INSERT statement to add a new record in my table. I want to be able to get the Autonumber UserID field of the newly created record but I am getting the following error: "Characters found after end of SQL statement" Code:
INSERT INTO tblUser (LoginName, UserPassword, EmailAddress, City) Values (@User, @UsrPassword, @EmailAddress, @City); SELECT @@IDENTITY As 'Identity'
What is wrong in my statement? How do I retrieve the Autonumber field of the newly created record? How do I handle if the LoginName and/or EmailAddress already exists?
I want to be able save this INSERT statement as an Access Query and call it from my C# code.
I'm trying to figure out what happened.I have have two Tables in SQLServer called "Contacts", and "Jobs"Whenever someone changes a record in either table I update two fieldscalled "Modby" and "Moddt" with a trigger. The Trigger may alsocontain other things as well.Here's the wierd thing.If the Modby Moddt statement is the first statement in the trigger Idon't get a "record changed by another user" but if it comes later inthe trigger I do.I think it has something to do with the LockDelay Key but I'm not sure.Any Ideas?
Purpose I would like to know if it is possible and if so how to implement exclusive access to a given record within in a database table.
Example For example, you can open a file system file with exclusive access so other processes cannot access the file until it is released. I would like to implement a solution that provides this same exclusive access at the database record level. Preferably a solution that does not require creating and managing table access state flags. (i.e. €“ FieldName.State = (Closed, Opened, Exclusive)) I would like for the database server to mange this solution and return an error status when trying to access a record that has been opened exclusively. Furthermore, I would like to avoid using triggers.
Application Utilization I€™m working on a system that has multiple threads that are each responsible managing data from the same normalized table. Each of these system threads work on the same unique record in parallel. Therefore it is possible that thread (0)€™s changes could be overwritten by thread (n)€™s. I would like to have each thread open the unique record exclusively and release it when finished. All of the other threads would loop until the record is released.
Questions
1. Is it possible to implement this at the server level?
2. What would be the easiest best practice for implementing this functional requirement?
Ok, to start I will say I am a novice so detailed solutions are much appreciated. I believe I am on the right track. Here is what I am trying to accomplish. I have a page that uses an xml driven google map. When you click on the map marker, the info bubble displays brief information about a community and a link specified from the xml file. I have specified the links in the xml file to pass a query string variable ex: /community.aspx?name=uniqueCommunityNameHere. I tested this by simply placing a label on the community.aspx page that restated the "name" value - works fine (first commented out line of Page_Load). Now I need to complete my VB function that pulls the data record from the database - based on the parameter input from the query string - when the page loads. So if the user clicks the link on the marker for community1, it will populate community.aspx with info about community1 from the database... if they click community7 it will display that community info etc. Data Table: "Community" Data Fields: ID, Name, Description, Address, City, State, Phone, SalesRep. ASPX Page Design Elements: lblID, lblName, lblDesc, lblAddress.... etc. Here is my start... I will need help with the sql statement for sure - how do I create a where clause from the query string parameter passed in? Thanks so much for your help!
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load'My initial test to see that the query string is working lblName.Text = Request("name").ToString() ' Get the community info when loading community.aspx for the user selected communityIf Not IsPostBack ThenLoadCommunityInfo(Request("name").ToString())End IfEnd SubPrivate Sub LoadCommunityInfo(ByVal community)' Define data objectsDim conn As SqlConnectionDim comm As SqlCommandDim reader As SqlDataReader ' Read the connection string from Web.configDim connectionString As String = ConfigurationManager.ConnectionStrings("CONHTConnectionString").ConnectionString' Initialize connectionconn = New SqlConnection(connectionString)' Create commandcomm = New SqlCommand("SELECT * FROM Community WHERE Name = " & community, conn)' Enclose database code in Try-Catch-FinallyTry' Open the connectionconn.Open()' Execute the commandreader = comm.ExecuteReader()' Populate the list of community information -> Make the labels.text = the database fields --> lblName.text = table-Community field-"Name"lblName.Text = "Name"lblDesc.Text = "Description"....' Close the readerreader.Close()Catch' Display error messagedbErrorLabel.Text = "Error loading the community information!<br />"Finally' Close the connectionconn.Close()End TryEnd Sub
I can't delete records for a SQL Server table when I attached the table to Microsoft Access 97. I time out when I try to delete the record. However I can query the table.
I use the standard ODBC setup, do I need to do anything else beside using the standard Access link.
Anyone know if there is method that can insert all record from a tablein an MS Access 2000 database to a table in MS SQL Server 2000database by a SQL statement? (Therefore, I can execute the statementin my program)--Posted via http://dbforums.com
I have table contains more columns  and first column have ID  int not null primary key  and auto increment by 1 seed by 1 the ID 165000 record  and instant Jump to 166000 and increment by 1 ...
I like to give First Name and Last Name in two different text box and then hit the delete button (command button). Then it will do a query to find the person and delete the corresponding record from the table. Any kind of help will be appreciated. Thank you.
I'm got a "folder" structure application which we'll be using as an in-house directory viewer. (In case you're wondering, it doesn't relate to any "real" folders, so using xp_cmdshell is out! )
Each folder and file record can have its own permissions, however these are assumed to inherit from the parent folder if no specific access rules have been set, basically in the same way file systems work. Each file record can only have one parent, and a folder can either have a parent or be at the root level.
Right now I'm having an issue with the inheritance of permissions. Say if I want to grant access to "Folder 1" to "Group A", then "Group B" shouldn't be able to see it. However, if I grant access to "File 1" in "Folder 1" to "Group B", then "Group B" should be able to see "Folder 1", but only see "File 1" and not the rest of the contents.
I thought I could do this with a CTE, but I'm having a bit of difficulty..
Here's the code:
CREATE TABLE #FileSystem ( FSIDINTEGER NOT NULL IDENTITY(1,1) PRIMARY KEY ,ParentFSIDINTEGER NULL ,NameVARCHAR(100) ,RecordTypeVARCHAR(1)-- (F)older, or Fi(L)e
In our company, after switching to Office 2007, Access 2007 runtime is installed on our general user machines. Everything is just fine and beautiful, except that there is one issue with runtime:
Several forms in my Access Project use stored procedures in SQL Server 2000 as their record source. When i try to open the forms in Access 2007 Runtime on user machines, i receive an error that "The record source dbo.Myprocedure speified on this form or report does not exist ". I use dbo.ProcName format and the forms open correctly in my full version Access. What could be the problem?
If these are all used up, and a 26th connection comes in. What happens? is the connection rejected? or does it sit in a queue, waiting to be given a connection?
hi i hv developed an application that runs on the local windows system and interfaces with the MSSQL 7.0 database server using ODBC DSN Connections. This application will be deployed over the LAN with over 100 users.
The MSSQL 7.0 server has only 5 user licenses that limits the concurrent usage to 5 users.
I need a solution whereby all users can access the SQL server database without adding more licenses
