I have a couple of tables I ported over to a new database. Everything is exactly the same from the legacy one to the new one. The back-end code that submits the user generated data to the database is also the same. When I submit changes to the database, all of the submitted information populates the correct columns but the column that stores the GUID populates with all 0's. When I enter in the columns manually using SQL Server Management Studio, the GUID gets populated as it does in the legacy version. Am I missing something?
I've had a similar issue with Entity Framework in the past, even though I have newid() set as default/initial value on the column. Due to time constraints, I didn't spend much time to resolve it and instead set the Guid property manually/explicitly to Guid.NewGuid() prior to saving.
When you ported over the tables, you must not have ported over the default value for one of the columns. E.g.
CREATE TABLE blah (
blahID UNIQUEIDENTIFIER PRIMARY KEY DEFAULT NEWID()
)
Related
I am having an issue with an SQLite database. I am using the SQLite ODBC from http://www.ch-werner.de/sqliteodbc/ Installed the 64-bit version and created the ODBC with these settings:
I open my Access database and link to the datasource. I can open the table, add records, but cannot delete or edit any records. Is there something I need to fix on the ODBC side to allow this? The error I get when I try to delete a record is:
The Microsoft Access database engine stopped the process because you and another user are attempting to change the same data at the same time.
When I edit a record I get:
The record has been changed by another user since you started editing it. If you save the record, you will overwrite the changed the other user made.
Save record is disabled. Only copy to clipboard or drop changes is available.
My initial attempt to recreate your issue was unsuccessful. I used the following on my 32-bit test VM:
Access 2010
SQLite 3.8.2
SQLite ODBC Driver 0.996
I created and populated the test table [tbl1] as documented here. I created an Access linked table and when prompted I chose both columns ([one] and [two]) as the Primary Key. When I opened the linked table in Datasheet View I was able to add, edit, and delete records without incident.
The only difference I can see between my setup and yours (apart from the fact that I am on 32-bit and you are on 64-bit) is that in the ODBC DSN settings I left the Sync.Mode setting at its default value of NORMAL, whereas yours appears to be set to OFF.
Try setting your Sync.Mode to NORMAL and see if that makes a difference.
Edit re: comments
The solution in this case was the following:
One possible workaround would be to create a new SQLite table with all the same columns plus a new INTEGER PRIMARY KEY column which Access will "see" as AutoNumber. You can create a unique index on (what are currently) the first four columns to ensure that they remain unique, but the new new "identity" (ROWID) column is what Access would use to identify rows for CRUD operations.
I had this problem too. I have a table with a primary key on a VARCHAR(30) (TEXT) field.
Adding an INTEGER PRIMARY KEY column didn't help at all. After lots of testing I found the issue was with a DATETIME field I had in the table. I removed the DATETIME field and I was able to update record values in MS-Access datasheet view.
So now any DATETIME fields I need in SQLite, I declare as VARCHAR(19) so they some into Access via ODBC as text. Not perfect but it works. (And of course SQLite doesn't have a real DATETIME field type anyway so TEXT is just fine and will convert OK)
I confirmed it's a number conversion issue. With an empty DATETIME field, I can add a time of 01-01-2014 12:01:02 via Access's datasheet view, if I then look at the value in SQLite the seconds have been rounded off:
sqlite> SELECT three from TEST where FLoc='1020';
2014-01-01 12:01:00.000
SYNCMODE should also be NORMAL not OFF.
Update:
If you have any text fields with a defined length (e.g. foo VARCHAR(10)) and the field contents contains more characters than the field definition (which SQLite allows) MS-Access will also barf when trying to update any of the fields on that row.
I've searched all similar posts as I had a similar issue with SQLite linked via ODBC to Access. I had three tables, two of them allowed edits, but the third didn't. The third one had a DATETIME field and when I changed the data type to a TEXT field in the original SQLite database and relinked to access, I could edit the table. So for me it was confirmed as an issue with the DATETIME field.
After running into this problem, not finding a satisfactory answer, and wasting a lot of time trying other solutions, I eventually discovered that what others have mentioned about DATETIME fields is accurate but another solution exists that lets you keep the proper data type. The SQLite ODBC driver can convert Julian day values into the ODBC SQL_TIMESTAMP / SQL_TYPE_TIMESTAMP types by looking for floating point values in the column, if you have that option enabled in the driver. Storing dates in this manner gives the ODBC timestamp value enough precision to avoid the write conflict error, as well as letting Access see the column as a date/time field.
Even storing sub-second precision in the date string doesn't work, which is possibly a bug in the driver because the resulting TIMESTAMP_STRUCT contains the same values, but the fractional seconds must be lost elsewhere.
I am having this problem intermittently with ServiceStack.Net OrmLite on SqLite.
My model class is using a Guid for the primary Id. My code sets a Guid.NewGuid() value to my model before saving, if the model is new.
I have set a breakpoint to verify that immediately before db.Save(myModel), myModel.Id is always a populated, unique Guid. However, the value committed to the table is NULL.
It seems after I create the database, it saves a the values correctly for a while, but then just starts saving NULLs for the Id! My code is doing the same thing throughout. This seems especially extraordinary to me, since OrmLite creates the column as a non-Nullable primary key.
Has anybody seen this issue, or know what might be causing it? Thank you.
This was caused by having an [AutoIncrement] attribute on the Guid Id. Oops!
I would like to monitor 10 tables with 1000 records per table. I need to know when a record, and which record changed.
I have looked into SQL Dependencies, however it appears that SQL Dependencies would only be able to tell me that the table changed, and not which record changed. I would then have to compare all the records in the table to find the modified record. I suspect this would be a problem for me as the records constantly change.
I have also looked into SQL Trigger's, however I am not sure if triggers would work for monitoring which record changed.
Another thought I had, is to create a "Monitoring" table which would have records added to it via the application code whenever a record is modified.
Do you know of any other methods?
EDIT:
I am using SQL Server 2008
I have looked into Change Data Capture which is available in SQL 2008 and suggested by Martin Smith. Change Data Capture appears to be a robust, easy to implement and very attractive solution. I am going to roll CDC on my database.
You can add triggers and have them add rows to an audit table. They can audit the primary key of the rows that changed, and even additional information about the changes. For instance, in the case of an UPDATE, they can record the columns that changed.
Before you write/implement your own take a look at AutoAudit :
AutoAudit is a SQL Server (2005, 2008) Code-Gen utility that creates
Audit Trail Triggers with:
Created, CreatedBy, Modified, ModifiedBy, and RowVersion (incrementing INT) columns to table
Insert event logged to Audit table
Updates old and new values logged to Audit table
Delete logs all final values to the Audit table
view to reconstruct deleted rows
UDF to reconstruct Row History
Schema Audit Trigger to track schema changes
Re-code-gens triggers when Alter Table changes the table
What version and edition of SQL Server? Is Change Data Capture available? – Martin Smith
I am using SQL 2008 which supports Change Data Capture. Change Data Capture is a very robust method for tracking data changes as I would like to. Thanks for the answer.
Here's an idea.You can have a flag on each table that every time a record is created or updated is filled with current datetime. Then when you notice that a record has changed set its flag to null again.Thus unchanged records have null in their flag field and you can query not null values to see which record has changed/created and when (and set their flags to null again) .
i have two tables
asset employee
assetid-pk empid-pk
empid-fk
now, i have a form to populate the asset table but it cant because of the foreign key constraint..
what to do?
thx
Tk
Foreign keys are created for a good reason - to prevent orphan rows at a minimum. Create the corresponding parent and then use the appropriate value as the foreign key value on the child table.
You should think about this update as a series of SQL statements, not just one statement. You'll process the statements in order of dependency, see example.
Asset
PK AssetID
AssetName
FK EmployeeID
etc...
Employee
PK EmployeeID
EmployeeName
etc...
If you want to "add" a new asset, you'll first need to know which employee it will be assigned to. If it will be assigned to a new employee, you'll need to add them first.
Here is an example of adding a asset named 'BOOK' for a new employee named 'Zach'.
DECLARE #EmployeeFK AS INT;
INSERT (EmployeeName) VALUES ('Zach') INTO EMPLOYEE;
SELECT #EmployeeFK = ##IDENTITY;
INSERT (AssetName, EmployeeID) VALUES ('BOOK',#EmployeeFK) INTO ASSET;
The important thing to notice above, is that we grab the new identity (aka: EmployeeID) assigned to 'Zach', so we can use it when we add the new asset.
If I understand you correctly, are you trying to build the data graph locally before persisting to the data? That is, create the parent and child records within the application and persist it all at once?
There are a couple approaches to this. One approach people take is to use GUIDs as the unique identifiers for the data. That way you don't need to get the next ID from the database, you can just create the graph locally and persist the whole thing. There's been a debate on this approach between software and database for a long time, because while it makes a lot of sense in many ways (hit the database less often, maintain relationships before persisting, uniquely identify data across systems) it turns out to be a significant resource hit on the database.
Another approach is to use an ORM that will handle the persistence mapping for you. Something like NHibernate, for example. You would create your parent object and the child objects would just be properties on that. They wouldn't have any concept of foreign keys and IDs and such, they'd just be objects in code related by being set as properties on each other (such as a "blog post" object with a generic collection of "comment" objects, etc.). This graph would be handed off to the ORM which would use its knowledge of the mapping between the objects and the persistence to send it off to the database in the correct order, perhaps giving back the same object but with ID numbers populated.
Or is this not what you're asking? It's a little unclear, to be honest.
I have a table which links to another table in the ASP.NET membership schema.
Problem is, all the PKs for the ASP.NET tables are uniqueidentifier so mine has to be too. When I add a SqlDatasource and call its Insert() method, I get the following error:
Cannot insert the value NULL into column 'DiscountCode', table 'CreamDb.dbo.CustomInfo1'; column does not allow nulls. INSERT fails.
The statement has been terminated.
The uniqueidentifier is also treated as an object (its data type), but there is no Guid data type. I had this problem before, but the schema was much simpler so I could fix it.
How can I go about fixing this? If I get rid of the data type part in the markup (so just leave the field/parameter name but not the data type stuff), I get another error so that is not possible.
Thanks
What do you mean by "there is no Guid data type"? What's wrong with System.Guid? Can't you just use Guid.NewGuid(), set the field appropriately, and do the insert?
EDIT: Just to give a bit more meat: attach an event handler to the Inserting event, and populate the field then, via the DbCommand returned by SqlDataSourceCommandEventArgs.Command. Or change the SQL used by the INSERT command to ask the database to populate the GUID field for you.
A popullar approach when dealing with references to the ASP.NET Membership Provider's data is, instead of keeping a proper foreign key to the GUIDs, instead store something like the LoweredUserName in your table. Then, use the Membership Provider's API to interact with the object you need. In some cases, you need an ObjectDataSource abstraction layer to accomplish CRUD scenarios.
Set the default value of the column in SQL Sever to "newid()".
Asp.net won't send the value, and the field will get a new guid.