I have a big file which I have loaded in a table in a netezza database using an ETL tool, lets call this database Staging_DB. Now, post some verifications, the content of this table needs to be inserted into similar structured table residing in another netezza DB, lets call this one PROD_DB. What is the fastest way to transfer data from staging_DB to PROD_DB?
Should I be using the ETL tool to load the data into PROD_DB? Or,
Should the transfer be done using external tables concept?
If there is no transformation need to be done, then better way to transfer is cross database data transfer. As described in Netezza documentation that Netezza support cross database support where the user has object level permission on both databases.
You can check permission with following command -
dbname.schemaname(loggenin_username)=> \dpu username
Please find below working example -
INSERT INTO Staging_DB..TBL1 SELECT * FROM PROD_DB..TBL1
If you want to do some transformation and than after you need to insert in another database then you can write UDT procedures (also called as resultset procedures).
Hope this will help.
One way you could move the data is by using Transient External Tables. Start by creating a flat file from your source table/db. Because you are moving from Netezza to Netezza you can save time and space by turning on compression and using internal formatting.
CREATE EXTERNAL TABLE 'C:\FileName.dat'
USING (
delim 167
datestyle 'MDY'
datedelim '/'
maxerrors 2
encoding 'internal'
Compress True
REMOTESOURCE 'ODBC'
logDir 'c:\' ) AS
SELECT * FROM source_table;
Then create the table in your target database using the same DDL in the source and just load it up.
INSERT INTO target SELECT * FROM external 'C:\FileName.dat'
USING (
delim 167
datestyle 'MDY'
datedelim '/'
maxerrors 2
encoding 'internal'
Compress True
REMOTESOURCE 'ODBC'
logDir 'c:\' );
I would write a SP on production db and do a CTAS from stage to production database. The beauty of SP is you can add transformations as well.
One other option is NZ migrate utility provided by Netezza and that is the fastest route I believe.
A simple SQL query like
INSERT INTO Staging_DB..TBL1 SELECT * FROM PROD_DB..TBL1
works great if you just need to do that.
Just be aware that you have to be connected to the destination database when executing the query, otherwise you will get an error code
HY0000: "Cross Database Access not supported for this type of command"
even if you have read/write access to both databases and tables.
In most cases you can simply change the catalog using a "Set Catalog" command
https://www-304.ibm.com/support/knowledgecenter/SSULQD_7.0.3/com.ibm.nz.dbu.doc/r_dbuser_set_catalog.html
set catalog='database_name';
insert into target_db.target_schema.target_table select source_db.source_schema.source_table;
Related
On the ETL server I have a DW user table.
On the prod OLTP server I have the sales database. I want to pull the sales only for users that are present in the user table on the ETL server.
Presently I am using an execute SQL task to fetch the DW users into a SSIS System.Object variable. Then using a for each loop to loop through each item (userid) in this variable and via a data flow task fetch the OLTP sales table for each user and dump it into the DW staging table. The for each is taking long time to run.
I want to be able to do an inner join so that the response is quicker, but I cant do this since they are on separate servers. Neither can I use a global temp table to make the inner join, for the same reason.
I tried to collect the DW users into a comma separated string variable and then using it (via string_split) to query into OLTP, but this is also taking more time at the pre-execute phase (not sure why exactly) even for small number of users.
I also am aware of lookup transform but that too will result in all oltp rows to be brought into the dw etl server to test the lookup condition.
Is there any alternate approach to be able to do an inner join by taking the list of users into the source?
Note: I do not have write permissions on the OLTP db.
Based on the comments, I think we can use a temporary table to solve this.
Can you help me understand this restriction? "Neither can I use a global temp table to make the inner join, for the same reason."
The restriction is since oltp server and dw server are separate so can't have global temp table common to both servers. Hope makes sense.
The general pattern we're going to do is
Execute SQL Task to create a temporary table on the OLTP server
A Data Flow task to populate the new temporary table. Source = DW. Destination = OLTP. Ensure Delay Validation = True
Modify existing Data Flow. Modify source to be a query that uses the temporary table i.e. SELECT S.* FROM oltp.sales AS S WHERE EXISTS (SELECT * FROM #SalesPerson AS SP WHERE SP.UserId = S.UserId); Ensure Delay Validation = True
A long form answer on using temporary tables (global to set the metadata, regular thereafter)
I don't use temp table in SSIS
Temporary tables, live in tempdb. Your OLTP and DW connection managers likely do not point to tempdb. To be able to reference a temporary table, local or global, in SSIS you need to either define an additional connection manager for the same server that points explicitly at tempdb so you can use the drop down in the source/destination components (technically accurate but dumb). Or, you use an SSIS Variable to hold the name of the table and use the ~From Variable~ named option in source/destination component (best option, maximum flexibility).
Soup to nuts example
I will use WideWorldImporters as my OLTP system and WideWorldImportersDW as my DW system.
One-time task
Open SQL Server Management Studio, SSMS, and connect to your OLTP system. Define a global temporary table with a unique name and the expected structure. Leave your connection open so the table structure remains intact during initial development.
I used the following statement.
DROP TABLE IF EXISTS #SO_70530036;
CREATE TABLE #SO_70530036(EmployeeId int NOT NULL);
Keep track of your query because we'll use it later on but as I advocate in my SSIS answers, perform the smallest task, test that it works and then go on to the next. It's the only way to debug.
Connection Managers
Define two OLE DB Connection Managers. WWI_DW uses points to the named instance DEV2019UTF8 and WWI_OLTP points to DEV2019EXPRESS. Right click on WWI_OLTP and select Properties. Find the property RetainSameConnection and flip that from the default of False to True. This ensures the same connection is used throughout the package. As temporary tables go out of scope when the connection goes away, closing and reopening a connection in a package will result in a fatal error.
These two databases on different instances so we can't cheat and directly comingle data.
Variables
Define 4 variables in SSIS, all of type String.
TempTableName - I used a value of ##SO_70530036 but use whatever value you specified in the One-time task section.
QuerySourceEmployees - This will be the query you run to generate the candidate set of data to go into the temporary table. I used SELECT TOP (3) E.[WWI Employee ID] AS EmployeeId FROM Dimension.Employee AS E WHERE E.[Is SalesPerson] = CAST(1 AS bit);
QueryDefineTables - Remember the drop/create statements from the on-time task? We're going to use the essence of them but use the expression builder to let us dynamically swap the table name. I clicked the ellipses, ..., on the Expression section and used the following "DROP TABLE IF EXISTS " + #[User::TempTableName] + "; CREATE TABLE " + #[User::TempTableName] + "( EmployeeId int NOT NULL);" You should be able to copy the Value from the row and paste it into SSMS to confirm it works.
QuerySales - This is the actual query you're going to use to pull your filtered set of sales data. Again, we'll use the Expression to allow us to dynamically reference the temporary table name. The prettified version of the expression would look something like
"SELECT
SI.InvoiceID
, SI.SalespersonPersonID
, SO.OrderID
, SOL.StockItemID
, SOL.Quantity
, SOL.OrderLineID
FROM
Sales.Invoices AS SI
INNER JOIN
Sales.Orders AS SO
ON SO.OrderID = SI.OrderID
INNER JOIN
Sales.OrderLines AS SOL
ON SO.OrderID = SOL.OrderID
WHERE
EXISTS (SELECT * FROM " + #[User::TempTableName] + " AS TT WHERE TT.EmployeeID = SI.SalespersonPersonID);"
Again, you should be able to pull the Value from the three queries and run them independently and verify they work.
Execute SQL Task
Add an Execute SQL task to the Control Flow. I named mine SQL Create temporary table My Connection Manager is WWI_OLTP and I changed the SQLSourceType to Variable and the SourceVariable is User::QueryDefineTables
Every time your package runs, the first thing it will do is establish create the temporary table. Which is good because SSIS is a metadata driven ETL engine and the next two steps would fail if the table didn't exist.
Data Flow Task - Prime the pump
This data flow is where we'll transfer DW data back to the OLTP system so can filter in the source system.
Drag a Data Flow Task onto the Control Flow. I named mine DFT Load Temp and before you click into it, right click on the Task and find the DelayValidation property and change this from the default of False to True. Normally, a package validates all metadata before actual execution begins as the idea is you want to know everything is good before any data starts moving. Since we're using temporary tables, we need to tell the execution engine "trust us, it'll be ready"
Double click inside the Data Flow Task.
Add an OLE DB Source. I named mine OLESRC SourceEmployees I use the connection manager WWI_DW. My data access mode changes to SQL command from variable and then I select my variable User::QuerySourceEmployees
Add an OLE DB Destination. I named mine OLEDST TempTableName and double clicked to configure it. The Connection Manager is WWI_OLTP and again, since the table lives in tempdb, we can't select it from the drop down. Change the Data access mode to Table name or view name variable - fast load and then select your variable name User::TempTableName. Click the Mapping tab and ensure source columns map to destination columns.
Data Flow Task - Transfer data
Finally, we will pull our source data, nicely filtered against the data from our target system.
Add an OLE DB Source. I named it OLESRC QuerySales. The Connection Manager is WWI_OLTP. Data access mode again changes to SQL command from variable and the variable name is User::QuerySales
From here, do whatever else you need to do to make the magic happen.
Instead of having 270k rows with an unfiltered query
I have 67k as there are only 3 employees in the temporary table.
Reference package
But wait, there's more!
Close out visual studio, open it back up and try to touch something in the data flows. Suddenly, there are red Xs everywhere! Any time you close a data flow component, it fires a revalidate metadata operation and guess what, it can't do that as the connection to the temporary table is gone.
The package will run fine, it will not throw VS_NEEDSNEWMETADATA but editing/maintenance becomes a pain.
If you switched from global temporary table to local, switch the table name variable's value back to a global and then run the define statement in SSMS. Once that's done, then you can continue editing the package.
I assure you, the local temporary table does work once you have the metadata set and you use queries via variables for source/destination.
No need for the global temporary table hack, or the SET FMTONLY OFF hack (which no longer works).
Just specify the result set metadata in the SQL query with WITH RESULT SETS. eg
EXEC ('
create table #t
(
ID INT,
Name VARCHAR(150),
Number VARCHAR(15)
)
insert into #t (Id, Name, Number)
select object_id, name, 12
from sys.objects
select * from #t
')
WITH RESULT SETS
(
(
ID INT,
Name VARCHAR(150),
Number VARCHAR(15)
)
)
If you need to parameterize the query, there's a bit of a catch because there are some limitations in how SSIS discovers parameters. SSIS runs sp_describe_undeclared_parameters, which doesn't really work with batches that call sp_executesql, because sp_executesql has a very unique way it handles parameters, one which you couldn't replicate with a user stored procedure.
So to parameterize the query you'll either need to pass the parameter values into the query using the "query from variable" and SSIS expressions, or push all this TSQL into a stored procedure.
I am trying to move tables from access to SQL Server programmatically.
I have some limitation in the system permissions, ie: I cannot use OPENDATASOURCE or OPENROWSET.
What I want to achieve is to transfer some table from Access to SQL Server and then work on that tables through vba (excel)/python and T-SQL.
The problem is in the timing that it is required to move the tables.
My current process is:
I work with vba macros, importing data from excel and making same transformation in access, to then import into the SQL Server
destroy the table in the server: "DROP TABLE"
re-importing the table with DoCmd.TransferDatabase
What I have notice is that the operation seems to be done based on a batch of rows and not directly. It is taking 1 minutes and half each 1000 rows. The same operation on Access it would have taken few seconds.
I understood that it is a specific way of SQL Server to use import by batches of 10 rows, probably to have more access on data: Micorsoft details
But in the above process I just want a copy the table from access to the SQL as fast as possible as then I would avoid cross platform links and I will perform operation only on the SQL Server.
Which would be the faster way to achieve this goal?
Why are functions like OPENDATASOURCE or OPENROWSET are blocked? Do you work in a bank?
I can't say for sure which solution is the absoute fastest, but you may want to consider exporting all Access tables as separate CSV files (or Excel files), and then run a small script to load each of those files into SQL Server.
Here is some VBA code that saves separate tables as separate files.
Dim obj As AccessObject, dbs As Object
Set dbs = Application.CurrentData
For Each obj In dbs.AllTables
If Left(obj.Name, 4) <> "MSys" Then
DoCmd.TransferText acExportDelim, , obj.Name, obj.Name & ".csv", True
DoCmd.TransferSpreadsheet acExport, acSpreadsheetTypeExcel9, obj.Name, obj.Name & ".xls", True
End If
Next obj
Now, you can very easily, and very quickly, load CSV files into SQL Server using Bulk Insert.
Create TestTable
USE TestData
GO
CREATE TABLE CSVTest
(ID INT,
FirstName VARCHAR(40),
LastName VARCHAR(40),
BirthDate SMALLDATETIME)
GO
BULK
INSERT CSVTest
FROM 'c:\csvtest.txt'
WITH
(
FIELDTERMINATOR = ',',
ROWTERMINATOR = '\n'
)
GO
--Check the content of the table.
SELECT *
FROM CSVTest
GO
--Drop the table to clean up database.
DROP TABLE CSVTest
GO
https://blog.sqlauthority.com/2008/02/06/sql-server-import-csv-file-into-sql-server-using-bulk-insert-load-comma-delimited-file-into-sql-server/
Also, you may want to consider one of these options.
https://www.online-tech-tips.com/ms-office-tips/ms-access-to-sql-database/
https://support.office.com/en-us/article/move-access-data-to-a-sql-server-database-by-using-the-upsizing-wizard-5d74c0df-c8cd-4867-8d07-e6e759d72924
ETL Script to dynamically map multiple execute sql resultset to multiple tables (table name based on sql file provided)
I have a source folder with sql files ( I can put it up as stored procedures as well ) . I know how to loop and execute sql tasks in a foreach container. Now the part where I'm stuck is I need to use the final result set of each sql queries and shove it into a table with the same name as the sql file.
So, Folder -> script1.sql , script2.sql etc -> ETL -> goes to table script1, table script2 etc.
EDIT : Based on the comment made by Joe, I just want to say that I'm aware of using insert within a script but I need to insert it onto a table in a different server.And Linked servers are not the ideal solutions
Any psuedocode or link to tutorials will be extremely helpful . Thanks!
I would add the table creation to the script. It is probably the simplest way to do this. If your script is Select SomeField From Table1, you could change it to Select SomeField Into Table script1 From Table1. Then there is no need to map in SSIS which is not easy to do from my experience.
I am trying to do a incremental load from Sql server 2008 to Netezza (Nps6) using SSIS.
Netezza 5.x version OLEDB driver used. I am using Table or View - Fast Load option with Maximum insert commit size = 0.
Here I am trying to insert few thousands of records to a Netezza table. This destination table contains millions of records. This Data flow task was taking a hours to complete. When I looked into the Netezza Administrator Active Queries I could see that a query like below was the problem,
SELECT * FROM Destination_Table;
The next step is an external table load like below,
insert into "destination_table"(col1, col2, col3)
select c0, c1, c2 from external '/dev/null' (c0, c1, c2) using (
remotesource odbc' delimiter ' ' escapechar '\' ctrlchars 'yes' crinstring 'yes' timeroundnanos 'yes' encoding 'internal' maxerrors 1
) ;
Can anyone help me understand why a SELECT * FROM the Destination Table is required for load. Or how a Netezza OLEDB driver works with SSIS.
Appreciate your help.
Without looking at details in your package, the behavior which you have explained occurs if you have not selected the Table or View -fast load option for your Data access mode in your OLE DB Destination component. The fast load option would internally use a BULK INSERT for uploading data into the destination table.
Using the Table or view behaves like a SELECT * and pulls all the columns. This access mode should be used only if you need all the columns of the table or view from the source to the destination.
The problem for you is that this option might not be appearing for you by default, since you are using Netezza.
See issue discussed here along with possible workarounds:
http://social.msdn.microsoft.com/Forums/en-US/sqlintegrationservices/thread/965b6d83-cf5e-405b-8784-7981e4386adc
Official bug report raised here:
https://connect.microsoft.com/SQLServer/feedback/details/569087
After installing OLEDB 6.x version this "SELECT * FROM DESTINATION TABLE" issue is not occurring. I could see a good performance improvement with OLEDB 6 version. But, If we are working on OLEDB 5.x version, i believe it is better to load to a stage table and then load to the destination table
How can I import CSV file data into SQL Server 2000 table? I need to insert data from CSV file to table twice a day. Table has more then 20 fields but I only need to insert value into 6 fields.
i face same problem before i can suggest start reading here. The author covers:"This is very common request recently – How to import CSV file into SQL Server? How to load CSV file into SQL Server Database Table? How to load comma delimited file into SQL Server? Let us see the solution in quick steps."
I need to insert data from CSV file to table twice a day.
Use DTS to perform the import, then schedule it.
For SQL 2000, I would use DTS. You can then shedule this as a job when your happy with it.
Below is a good Microsoft link explaining how to use it.
Data Transformation Services (DTS)
You describe two distinct problems:
the CSV import, and
the extraction of data into only those 6 fields.
So break your solution down into two steps:
import the CSV into a raw staging table, and
then insert into your six 'live' fields from that staging table.
There is a function for the first part, called BULK INSERT, the syntax looks like this:
BULK INSERT target_staging_table_in_database
FROM 'C:\Path_to\CSV_file.csv'
WITH
(
DATAFILETYPE = 'CHAR'
,FIRSTROW = 2
,FIELDTERMINATOR = ','
,ROWTERMINATOR = '\n'
);
Adjust to taste, and consult the docs for more options. You might also want to TRUNCATE or DELETE FROM your staging table before doing the bulk insert so you don't have any old data in there.
Once you get the information into the database, doing an UPDATE or INSERT into those six fields should be straightforward.
You can make of use SQL Server Integration services(SSIS). It's jusy one time task to create the Package. Next time onwards just run that package.
You can also try Bulk Insert as daniel explained.
You can also try Import export wizard in SQL Server 2000.