Scenario:
I have a set of test data that needs to be deployed to our build server daily (our build server database is first overwritten with the current live database, and has all data over a month old removed).
This test data has foreign key references within it which need to stay.
I can't simply switch on IDENTITY_INSERT as the primary keys may clash with data that is already in the database (because we aren't starting from a blank database).
The test data needs to be able to be regenerated fairly regularly, so the though of going through the deploy script and fudging the id columns to be something outlandish (or a negative number for instance) and then changing the related foreign key columns to be the same id every time we regenerate the data doesn't thrill me.
Ideally I would like to know if there is a tool which can scan a database, pick up the foreign key constraints and generate the insert scripts accordingly, something like:
INSERT INTO MyTable VALUES('TEST','TEST');
DECLARE #Id INT;
SET #Id = (SELECT ##IDENTITY)
INSERT INTO MyRelatedTable VALUES(#Id,'TEST')
It sounds like you want to look into an ETL process that copes with the change in id. As you're using SQL Server, you can look at the OUTPUT clause - use this to build up some temporary tables that can map the "old" id to the "new" id for each primary key to map the foreign keys when migrating the "child" tables.
Related
I have a table on premise that is about 21 million rows with a primary key constraint and when I search that table, there are no duplicates. This table is in an OLTP application database that is constantly moving.
I have the exact same table in Azure which has the same primary key constraint. This table is not an application table, it's just a copy of the one that is on-premise (the goal is to use this one for ad hoc queries, as a source for other systems, etc.).
When I use Azure Data Factory to select all_columns from table on premise to the table in Azure, it returns a violation of the primary key constraint. No matter how many times I run this data factory pipeline, it comes back with a primary key violation for duplicate keys (the keys are always changing though).
So I dropped the primary key constraint in Azure and ran the pipeline again, and sure enough, duplication exists.
Upon investigation, it appears that the on-premise database is doing an insert new record then update the old record to inactivate it. So for a fraction of a second, there are two active rows that ADF is grabbing to then try to insert into the table in Azure which of course fails because of duplicate primary keys.
Now to the best of my knowledge, this shouldn't be possible. You can't insert a new row that violates the primary key constraint. But ADF seems to be grabbing all the data and some of those rows are mid-flight where the insert has happened and the update to inactivate the old row hasn't happened yet.
For those that are curious, the insert happens and the update of the old row happens within less than a second... it's typically 10-20 microseconds. I don't know how this is possible and I don't know how to fix it (because I can't modify the application code). The database for the on-premise database is a SQL Server 2000 database and Azure SQL is an Azure SQL database.
Try with readpast hint. It should not select any rows in locking state.
SELECT * FROM yourtable WITH (readpast)
Since you have create_date and updated_date column then you can select rows older than 5 seconds to avoid duplication.
select * from yourtable where created_date<=dateadd(second,-5,getdate()) and updated_date<=dateadd(second,-5,getdate());
Need to enable the Fault tolerance in a Pipeline Azure Data Factory
Copy data from a Source SQL to a Sink SQL database. A primary key is defined in the sink SQL database, but no such primary key is defined in the source SQL server. The duplicated rows that exist in the source cannot be copied to the sink. Copy activity copies only the first row of the source data into the sink. The subsequent source rows that contain the duplicated primary key value are detected as incompatible and are skipped.
To configure Json Definition skip the incompatible rows in copy activity "enableSkipIncompatibleRow": true
Please Refer: https://learn.microsoft.com/en-us/azure/data-factory/copy-activity-fault-tolerance
If possible to modify your application, need to check the Primary key constraint before insert or update using EXISTS() function.
Example:
IF EXISTS(SELECT * FROM Table_Name WHERE primary key condition)
BEGIN
UPDATE Table_Name
SET Col_Name= value
WHERE condition
END
ELSE
BEGIN
INSERT INTO Table_Name ( col_Name1,col_Name2,,.. )
VALUES ( ‘’,’’,’’,….)
END
Scenario: I'm copying data from Azure Table Storage to an Azure SQL DB using an upsert stored procedure like this:
CREATE PROCEDURE [dbo].[upsertCustomer] #customerTransaction dbo.CustomerTransaction READONLY
AS
BEGIN
MERGE customerTransactionstable WITH (HOLDLOCK) AS target_sqldb
USING #customerTransaction AS source_tblstg
ON (target_sqldb.customerReferenceId = source_tblstg.customerReferenceId AND
target_sqldb.Timestamp = source_tblstg.Timestamp)
WHEN MATCHED THEN
UPDATE SET
AccountId = source_tblstg.AccountId,
TransactionId = source_tblstg.TransactionId,
CustomerName = source_tblstg.CustomerName
WHEN NOT MATCHED THEN
INSERT (
AccountId,
TransactionId,
CustomerName,
CustomerReferenceId,
Timestamp
)
VALUES (
source_tblstg.AccountId,
source_tblstg.TransactionId,
source_tblstg.CustomerName,
source_tblstg.CustomerReferenceId,
source_tblstg.Timestamp
);
END
GO
where customerReferenceId & Timestamp constitute the composite key for the CustomerTransactionstable
However, when I update the rows in my source(Azure table) and rerun the Azure data factory, I see this error:
"ErrorCode=FailedDbOperation,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=A
database operation failed with the following error: 'Violation of
PRIMARY KEY constraint 'PK_CustomerTransactionstable'.
Cannot insert duplicate key in object
'dbo.CustomerTransactionstable'. The duplicate key value is
(Dec 31 1990 12:49AM, ABCDEFGHIGK).\r\nThe statement has been
terminated.',Source=.Net SqlClient Data
Provider,SqlErrorNumber=2627,Class=14,ErrorCode=-2146232060,State=1,Errors=[{Class=14,Number=2627,State=1,Message=Violation
of PRIMARY KEY constraint 'PK_CustomerTransactionstable'"
Now, I have verified that there's only one row in both the source and sink with a matching primary key, the only difference is that some columns in my source row have been updated.
This link in the Azure documentation speaks about the repeatable copying, however I don't want to delete rows for a time range from my destination before inserting any data nor do I have the ability to add a new sliceIdentifierColumn to my existing table or any schema change.
Questions:
Is there something wrong with my upsert logic? If yes, is there a better way to do upsert to Azure SQL DBs?
If I choose to use a SQL cleanup script, is there a way to delete only those rows from my Sink that match my primary key?
Edit:
This has now been resolved.
Solution:
The primary key violation will only occur if it's trying to insert a
record which already has a matching primary key. In my case there
although there was just one record in the sink, the condition on which
the merge was being done wasn't getting satisfied due to mismatch
between datetime and datetimeoffset fields.
Have you tried it using ADF Data Flows with Mapping Data Flows instead of coding it through a stored procedure? It may be much easier for you for upserts with SQL.
With an Alter Row transformation, you can perform Upsert, Update, Delete, Insert via UI settings and picking a PK: https://learn.microsoft.com/en-us/azure/data-factory/data-flow-alter-row
You would still just need a Copy Activity prior to your Data Flow activity to copy the data from Table Storage. Put it in a Blob folder and then Data Flow can read the Source from there.
I am new to SSIS packages and just require assistance on how to transfer data from one data source onto my own database.
Below is my data flow:
Now I have a ODBC Source (Http_Requests Source) where I take data from a PostgreSQL database table (see screenshot below for table columns and data):
Below is the OLE DB destination where it has the table I want to transfer the data to (this table is currently blank):
Now I tried to start debugging to extract the data but I get a few errors (displayed below):
I am a complete novice so I would like some guidance on what I need to include in order to get this SSIS package to transfer data across. Would I need to include a merge statement and how do I apply it. I heard you can write a merge as a proc and call on the proc as a sql command. Does that mean I will need to write a proc in SSMS and then call on it within the OLE DB Destination?
If somebody can provide an example and screenshot then that would be very helpful as I am really new to SSIS.
Thank you,
Check constraint on destination table or disable them before running it.
Below are query you can use.
-- Disable all table constraints
ALTER TABLE YourTableName NOCHECK CONSTRAINT ALL
-- Enable all table constraints
ALTER TABLE YourTableName CHECK CONSTRAINT ALL
Tick keep identity
box or drop primary key on the table. After you apply the changes do not forget to refresh metadata by opening the mappings in sis.
the error means that PerformanceId is an IDENTITY column on your destination table. IDENTITY columns are read only unless you tell it otherwise. So if we were in tSQL to be able to insert IDENTITY we would turn on IDENTITY_INSERT. Because you are in SSIS you can accomplish the same thing by checking the "keep identity" box.
HOWEVER when ever you get an error like this it is usually a sign that you should NOT be mapping ID to Performance ID. The question you have to ask is the Identity from your source supposed to be the identity of the destination table? Usually not, most of the time it would be another column as a surrogate key. Then you have to understand if it is even possible. because if there is a unique constraint or primary key then the identity cannot repeat which means you have to know that your source's id column will not cause a duplicate primary key violation.
More than likely the actual fix if for you to uncheck ID from the source and ignore the value.
The column PerformanceID (in the target) is almost certainly an identity column and that is why it is not working. You may not want to transfer it (and have SQL Server generate values for PerformanceID or you can check 'Keep Identity.'
We have developed a large data migration from one DB schema to the other. We had built it based on the idea that the destination DB would be empty, however months ago we started putting clients on the new application which means their data is being housed in the new schema (the destination DB).
Now we're in a situation where the primary keys could overlap from the source to the destination DB and we're struggling to come up with a solution. The only solution I can think of is to check if the ID exists in the destination, updated the ID in the source to be 1 more than the greatest ID in the destination, and then migrate the record. This seems really cumbersome to have to do for hundreds of tables. Any ideas?
Sorry I don't know anything about SSIS but the following are a few ways to solve the problem using SQL.
When inserting into the destination tables, do not insert identities. As rows are inserted, capture the newly inserted identities and the old identities in a mapping table, see MERGE + OUTPUT INTO. Use the mapping table to update the tables that haven't been inserted, substituting the old identities with the new identities.
Of course for this to work, insertion into tables has to be done in an order that won't cause foreign key or constraint violations.
If you're not into doing all that, and you can lock users out of tables for short periods of time, DBCC CHECK INDENT could be used to 'reserve' identities. These new identities can then be used to update the old data and then insert with SET IDENTITY_INSERT ON.
I wanted to modify a column in a sql server 2005 table to IDENTITY(1,1)
Incidentally this table is empty and the column to be changed is a primary key.
This column is also a foreign key for two other tables.
After googling I found that you cannot use Alter table syntax to modify a column and make it an indentity column.
Link #1 : How do I add the identity property to an existing column in SQL Server
Link #2 : Adding an identity to an existing column -SQL Server
I ended up checking the dependent tables (2 of them) removing the foreign keys (generated the script from SSMS) then dropping the main table then re-creating with identity. (could try the rename option here as well)
Then re-created the foreign keys for the earlier dependent two tables.
But all this was manual work, any scripts or SPs out there to make this easier.
Ideally all these steps would be done by such a script/tool/utility:
Check dependent tables keys
Generate Create and drop foreign key scripts for this
Generate create script for the main table
drop the main table (or rename the table if the table has data)
re-create the table with identity column enabled
re-create foreign keys
You can use SSMS to generate a script (Edit a table, save script), but otherwise it's a manual process as you identified.
The SSMS scripts will pick up dependencies etc. For this kind of work, I tend to use SSMS to generate a basic script, pimp it a bit, run it carefully, then use a comparison tool (such as Red Gate compare) to generate a safer version.
Edit: The SSMS error is not an error, it's a safety check that can be switched off
(This is merely a follow-up to gbn's post with more details -- it isn't all that easy to figure this stuff out.)(
It isn't impossible to write a utility to do this, just very complex and very hard. Fortunately, Microsoft has already done it -- its called SSMS (or SMO?). To generate such a script:
In the Object Explorer, drill down to the database and table that you want to modify
Right click and select Design
Make the desired changes to the one table in the design screen. It's reasonably intuitive.
To add/remove the identity property, select the column in the upper pane, and in the lower pane/"Column Properties" tab, expand and configure the settings under "Identity Specification".
To generate a script to implement all your changes, incorporating all the dependent key changes, click on the "Generate Change Script" toolbar button. This is also an option under the "Table Designer" menu.
I also do this to generate scripts (that I later modify--SSMS doesn't always produce the most efficient code.) Once done, you can exit out without saving your changes -- leaving you a DB you can test your new script on.
drop the pk and build the same datatype column
copy the data of the column which you want to set identity to the new column.
drop the old column
reset primary key
ALTER TABLE UserRole
DROP CONSTRAINT PK_XX
ALTER TABLE XX
ADD newX int not null identity(1,1) primary key
update XX set newX = oldX
alter table XX
DROP COLUMN oldX
this is the simplest way to set identity column.
if you don't want to use the long generated script.