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Posted to users@nifi.apache.org by Aruna Sankaralingam <Ar...@Cormac-Corp.com> on 2017/10/11 15:25:46 UTC
Transformations using Nifi
I am trying to see what kind of transformations that can be done in nifi and how.
Now I have a basic flow that takes CSV from the local dir and puts into s3 and loads into postgres database.
There are 4 columns in my test file 3 of which are string and one is an integer field. I would like to do the following before I load the data into postgres. If someone can help me on how to go about these, it will be great.
1. Convert one of the string columns to upper case
For converting to upper case, I was told to use the Update Record processor but my version is 1.2.0 and the update record processor is not available.
2. Postgres has an extra column called "Load_Date" in which I would like to load the current date with timestamp when the flow is run
3. If the integer column has more than 5 digits, I would like to take only the first 5 digits and load to the table
4. There is a look up table in postgres. I would like to check if the first column value is present in the look up table and if yes, proceed ahead and if not ignore the record
I am trying to learn nifi so I would really appreciate any kind of help here. Is there any training available online that I can take in order to understand and do all these?
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Re: Transformations using Nifi
Posted by Koji Kawamura <ij...@gmail.com>.
Hi Aruna,
If you can not upgrade from NiFi 1.2.0, then I think the best bed is using:
ScriptedReader or ScriptedRecordSetWriter for data conversion #1, 2 and 3.
As Russ mentioned, EL might be helpful when you implement the scripted
components.
#4 is a bit harder since it requires a database connection, but doable, I
don't know it works efficiently though..
Alternative approach would be create a temporary table, insert rows as they
are, then perform a insert/update query using the temporary table and
postgresql lookup table such as:
"insert into X select a, b, c, from T inner join L on X.j = T.j where d =
..."
Probably data conversion #1, 2, and 3 can be performed from this query as
well.
Thanks,
Koji
On Thu, Oct 12, 2017 at 11:50 PM, Russell Bateman <ru...@windofkeltia.com>
wrote:
> Aruna,
>
> I don't think there is any generalized NiFi training course yet. I started
> writing a book a year ago, but it's a pretty thankless task and takes a lot
> of time. I mostly write custom processors so I tend to see the world
> differently from most "user" users of NiFi. When I answer questions, which
> I don't do too much, I often tell an impractical story that doesn't answer
> the question asked.
>
> Now, I haven't done much database work at all, so I'm not going to be too
> much help to you. However, looking at your questions, particularly the one
> about obtaining the current date when the flow is run (#2) and also #3, I
> would suggest that you study the NiFi Expression Language. This would allow
> you to insert the "now" date into your flow at some point.
>
> The other suggestions I have are to experiment, which I'm sure you're
> doing, and Google hard for help. For this forum, which is filled with very
> nice and helpful people, you'll tend to get a lot more and better help if
> you come in with a very specific question rather than a list of things or a
> general, "help me" sort of plea.
>
> Cheers,
>
> Russ
>
> P.S. NiFi absolutely rocks, which you'll see as soon as you get over your
> initial hump here. But, you're on the right track.
>
> On 10/12/2017 08:16 AM, Aruna Sankaralingam wrote:
>
> Hi,
>
>
>
> Could you someone please help me with these requirements in the email
> below?
>
>
>
> Thanks
>
> Aruna
>
>
>
> *From:* Aruna Sankaralingam [mailto:Aruna.Sankaralingam@Cormac-Corp.com
> <Ar...@Cormac-Corp.com>]
> *Sent:* Wednesday, October 11, 2017 11:26 AM
> *To:* users@nifi.apache.org
> *Subject:* Transformations using Nifi
>
>
>
> I am trying to see what kind of transformations that can be done in nifi
> and how.
>
> Now I have a basic flow that takes CSV from the local dir and puts into s3
> and loads into postgres database.
>
> There are 4 columns in my test file 3 of which are string and one is an
> integer field. I would like to do the following before I load the data into
> postgres. If someone can help me on how to go about these, it will be great.
>
> 1. Convert one of the string columns to upper case
>
> *For converting to upper case, I was told to use the Update Record
> processor but my version is 1.2.0 and the update record processor is not
> available. *
>
>
>
> 2. Postgres has an extra column called “Load_Date” in which I would
> like to load the current date with timestamp when the flow is run
>
> 3. If the integer column has more than 5 digits, I would like to
> take only the first 5 digits and load to the table
>
> 4. There is a look up table in postgres. I would like to check if
> the first column value is present in the look up table and if yes, proceed
> ahead and if not ignore the record
>
>
>
> I am trying to learn nifi so I would really appreciate any kind of help
> here. Is there any training available online that I can take in order to
> understand and do all these?
>
>
>
>
>
Re: Transformations using Nifi
Posted by Russell Bateman <ru...@windofkeltia.com>.
Aruna,
I don't think there is any generalized NiFi training course yet. I
started writing a book a year ago, but it's a pretty thankless task and
takes a lot of time. I mostly write custom processors so I tend to see
the world differently from most "user" users of NiFi. When I answer
questions, which I don't do too much, I often tell an impractical story
that doesn't answer the question asked.
Now, I haven't done much database work at all, so I'm not going to be
too much help to you. However, looking at your questions, particularly
the one about obtaining the current date when the flow is run (#2) and
also #3, I would suggest that you study the NiFi Expression Language.
This would allow you to insert the "now" date into your flow at some point.
The other suggestions I have are to experiment, which I'm sure you're
doing, and Google hard for help. For this forum, which is filled with
very nice and helpful people, you'll tend to get a lot more and better
help if you come in with a very specific question rather than a list of
things or a general, "help me" sort of plea.
Cheers,
Russ
P.S. NiFi absolutely rocks, which you'll see as soon as you get over
your initial hump here. But, you're on the right track.
On 10/12/2017 08:16 AM, Aruna Sankaralingam wrote:
>
> Hi,
>
> Could you someone please help me with these requirements in the email
> below?
>
> Thanks
>
> Aruna
>
> *From:*Aruna Sankaralingam [mailto:Aruna.Sankaralingam@Cormac-Corp.com]
> *Sent:* Wednesday, October 11, 2017 11:26 AM
> *To:* users@nifi.apache.org
> *Subject:* Transformations using Nifi
>
> I am trying to see what kind of transformations that can be done in
> nifi and how.
>
> Now I have a basic flow that takes CSV from the local dir and puts
> into s3 and loads into postgres database.
>
> There are 4 columns in my test file 3 of which are string and one is
> an integer field. I would like to do the following before I load the
> data into postgres. If someone can help me on how to go about these,
> it will be great.
>
> 1.Convert one of the string columns to upper case
>
> /For converting to upper case, I was told to use the Update Record
> processor but my version is 1.2.0 and the update record processor is
> not available. /
>
> 2.Postgres has an extra column called “Load_Date” in which I would
> like to load the current date with timestamp when the flow is run
>
> 3.If the integer column has more than 5 digits, I would like to take
> only the first 5 digits and load to the table
>
> 4.There is a look up table in postgres. I would like to check if the
> first column value is present in the look up table and if yes, proceed
> ahead and if not ignore the record
>
> I am trying to learn nifi so I would really appreciate any kind of
> help here. Is there any training available online that I can take in
> order to understand and do all these?
>
RE: Transformations using Nifi
Posted by Aruna Sankaralingam <Ar...@Cormac-Corp.com>.
Hi,
Could you someone please help me with these requirements in the email below?
Thanks
Aruna
From: Aruna Sankaralingam [mailto:Aruna.Sankaralingam@Cormac-Corp.com]
Sent: Wednesday, October 11, 2017 11:26 AM
To: users@nifi.apache.org
Subject: Transformations using Nifi
I am trying to see what kind of transformations that can be done in nifi and how.
Now I have a basic flow that takes CSV from the local dir and puts into s3 and loads into postgres database.
There are 4 columns in my test file 3 of which are string and one is an integer field. I would like to do the following before I load the data into postgres. If someone can help me on how to go about these, it will be great.
1. Convert one of the string columns to upper case
For converting to upper case, I was told to use the Update Record processor but my version is 1.2.0 and the update record processor is not available.
2. Postgres has an extra column called "Load_Date" in which I would like to load the current date with timestamp when the flow is run
3. If the integer column has more than 5 digits, I would like to take only the first 5 digits and load to the table
4. There is a look up table in postgres. I would like to check if the first column value is present in the look up table and if yes, proceed ahead and if not ignore the record
I am trying to learn nifi so I would really appreciate any kind of help here. Is there any training available online that I can take in order to understand and do all these?
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