I have an SSIS package that takes data from a csv file goes through a data conversion to convert data type then imports into a database.
I wanted to remove part of a string from a column before importing it into the database so I included a derived column transformation.
I put the derived column task before the data conversion task. I set the Derived column to replace the column I want to change then put my expression in to replace the part of string.
It then goes to the data conversion and then to the import to database task. when I query the database it has put all the data from column 1 field into column 2 field it has not put the derived data in the column 2 field as it should because the fields are all mapped correctly.
has anyone else come across this?
I had set up everything correctly with my mappings my issue was in my REPLACE Expression in the derived column transformation task I was referencing column1 not column 2. have now resolved this.
Related
I've multiple csv files and multiple tables.
The table name is file name and column name is first row of csv file.
Now I want to add default value of empty string to the sink table.
Consider my scenario,
employee:
id int, name varchar, is_active bit NULL
employee.csv:
id|name|is_active
1|raja|
Now I'm trying to copy the csv data to PostgreSQL table its throwing error.
Expected result is default value if its empty value.
You can use NULLIF in PostgreSQL:
NULLIF(argument_1,argument_2);
The NULLIF function returns a null value if argument_1 equals to argument_2, otherwise it returns argument_1.
This way you can replace NULL value with some other value
If your error is related to Type mismatch then consider typecasting the column first
Thanks!
As per the issue, tried to repro the scenario and here is the following outcome which was successfully copied. You have to use
Source Dataset: employee.csv from Azure Blob Storage
Sink Dataset : Here, I have used the sink as Azure SQL DB for some limitations but as you have used PostgreSQL is almost similar.
Copy Activity Settings:
Under the mapping settings there will be type conversion, where you have to import schema else you can dynamically add
Output:
Alternative to use DataFlow - if you have multiple data fields, you need to use the derived column transformation to generate new columns in your data flow or to modify existing fields.
For more details, refer Derived column transformation in mapping data flow.
You can even refer to this Microsoft Q&A post for more insights: Copy Task failure because of conversion failure
So for my previous homework, we were asked to import a csv file with no columns names to impala, where we explicitly give the name and type of each column while creating the table. However, now we have a csv file but with column names given, in this case, do we still need to write down the name and type of it even it is provided in the data?
Yes, you still have to create an external table and define the column names and types. But you have to pass the following option right at the end of the create table statement
tblproperties ("skip.header.line.count"="1");
-- Once the table property is set, queries skip the specified number of lines
-- at the beginning of each text data file. Therefore, all the files in the table
-- should follow the same convention for header lines.
My Source File is (|) Pipe Delimited text file(.txt). I am trying load the file into SQL Server 2012 using SSIS(SQL Server Data Tools 2012). I have three columns. Below is the example for how data in file looks like.
I am hoping my package should fail as this is pipe(|) delimited instead my package is a success and the last row in the third column with multiple Pipes into last column.
My Question is Why is't the package failing? I believe it has corrupt data because it has more number of columns if we go by delimiter?
If I want to fail the package what are my options,If number of delimiters are more than the number columns?
You can tell what is happening if you look at the advanced page of the flat file connection manager. For all but the last field the delimiter is '|', for the last field it is CRLF.
So by design all data after the last defined pipe and the end of the line (CRLF) is imported into your last field.
What I would do is add another column to the connection manager and your staging table. Map the new 'TestColumn' in the destination. When the import is complete you want to ensure that this column is null in every row. If not then throw an error.
You could use a script task but this way you will not need to code in c# and you will not have to process the file twice. If you are comfortable coding a script task and / or you can not use a staging table with extra column then that will be the only other route I could think of.
A suggestion for checking for null would be to use an execute sql task with single row result set to integer. If the value is > 0 then fail the package.
The query would be Select Count(*) NotNullCount From Table Where TestColumn Is Not Null.
You can write a script task that reads the file, counts the pipes, and raises an error if the number of pipes is not what you want.
I am working on a project where there are 700 columns in a remote server and our destination table have columns that starts with underscore for example if there is a "SchoolName" column in the remote server, on our destination table we would have "_SchoolName" or "_School_Name" column. We use to use DTS package to import data "which doesn't use column name to map, instead it uses the order of the column on the select statement to map the column in the destination table". Now we would like upgrading our DTS package to SSIS, but mapping 700 columns manually has been a nightmare. Is there any way we can map columns based on the column orders instead of column name?
Aliases for each column should work .
If migration is state forward then Biml is a good option .
Link
I'm using SSIS to import data from one DB to another existing DB. Some columns in the destination tables do not exist in the source tables. Seems the Import & Export Wizard only allows me to select unmapped columns from the source and match them with these new columns in the destination. I'd like to be able to just provide one piece of data to import into all rows of these new columns.
Would like to use the GUI if possible because I'm not skilled at writing scripts. Thanks!
In SSIS, you can add a "derived column" component that will add columns to the buffer rows with the value you want (either a string or an expression).
I don't believe this is possible in the GUI. However, it would be a simple script after the data is loaded with SSIS:
UPDATE table SET newcolumn = new value
If you need to filter the rows, just add
WHERE column = value ...
You could change your source to a select query and list out the columns along with the static value you want to map.
SELECT SOURCECOLUMN_1,SOURCECOLUMN_2,....,SOURCECOLUMN_N,'VALUE' AS DESTINATIONCOLUMN FROM Source_Table
My original thought was that you could use the query right in the Import & Export wizard. you can obviously do alot more if you go in and edit the package, but it sounded like you didn't have much expereince with that. Here is how you would do this in the wizard.
After you have selected your source and destination databases you can Specify Table Copy or Query. Select the Write a query to specify the data to transfer option
On the next screen enter the query listing out all of the columns and add in your static columns.
On the Next screen You will need to select the Destination table or it will default to creating a new table named Query. You should be able to choose from the drop down. As long as you aliased your extra columns with the same names it should map correctly. You can go in and edit mappings here if needed.
You can then save off the SSIS package and it will source form the query.
Alternatively if you already have the SSIS pacakge created without the extra columns you can go in to the Data Flow and change the Data access mode in the OLE DB Source to be a SQL Command instead of a table or view. Add your query here.
You can then go into the properties of the OLE DB Desitination in the Dataflow and map the new column. You could also add in a derived column as #DominicGoulet by adding in a Dervied Column task and putting your static information here and then mapping. If you want to see that solution too let me know.