I need to import data from the inner joined tables of one db to a table of another db using Talend ETL tool.How can i do that?
Iam just new to talend.
How can i inner join the tables using condition in talend
Based on your requirement there would be multiple ways to achieve this.
One approach -
Use tMSSqlInput (for Sql Server - this would change based on your source database) and mention the required attributes to make the connection. In "Query" section - write your complete query involving the three different tables -
Once done, use tMap (to transform your data as per destination table) if required and then tMSSqlOutput (for Sql Server - this would change based on your destination database) to write the data to your table which would reside in another database. In connection properties make sure your configure the database correctly.
For tMSSqlOutput do check the properties - Use Batch/Batch Size & Commit every.
Sample job flow -
Now, another approach could be using bulk feature. You would be able to use tMSSqlOutputBulk to output the data retrieved from your source database into a file and then use tMSSqlBulkExec to bulk load the data from file into your destination table in your destination database.
Sample flow -
Note: Always compare which would be solution would be best fit by comparing the performance of all the available solutions.
Related
I am new to talend and need guidance on below scenario:
We have set of 10 Json files with different structure/schema and needs to be loaded into 10 different tables in Redshift db.
Is there a way we can write generic script/job which can iterate through each file and load it into database?
For e.g.:
File Name: abc_< date >.json
Table Name: t_abc
File Name: xyz< date >.json
Table Name: t_xyz
and so on..
Thanks in advance
With Talend Enterprise version one can benefit of dynamic schema. However based on my experiences with json-s they are somewhat nested structures usually. So you'd have to figure out how to flatten them, once thats done it becomes a 1:1 load. However with open studio this will not work due to the missing dynamic schema.
Basically what you could do is: write some java code that transforms your JSON into CSV. Use either psql from commandline or if your Talend contains new enough PostgreSQL JDBC driver then invoke the client side \COPY from it to load the data. If your file and the database table column order matches it should work without needing to specify how many columns you have, so its dynamic, but the data newer "flows" through talend.
Really not cool but also theoretically possible solution: If Redshift supports JSON (Postgres does) then one can create a staging table, with 2 columns: filename, content. Once the whole content is in this staging table, INSERT-SELECT SQL could be created that transforms the JSON into tabular format that can be inserted into the final table.
However, with your toolset you probably have no other choice than to load these files with 1 job per file. And I'd suggest 1 dedicated job to each file. They would each look for their own files and triggered / scheduled individually or be part of a bigger job where you scan the folders and trigger the right job for the right file.
Not able to load multiple tables, getting error:
Exception in component tMysqlInput_1 (MYSQL_DynamicLoading)
java.sql.SQLException: Bad format for Timestamp 'GUINESS' in column 3
One table works fine. Basically after first iteration the second table trying to use the schema
of the first table. Please help, how to edit the component to make it
correct. Trying to load actor & country table from sakila DB mysql to
a another DB on the same server. Above image is for successful one table
dynamic loading.
you should not use tMysqlInput if output schemas differ. For this case there is no way around tJavaRow and custom code. I however cannot guess what happens in tMap, so you should provide some more details about what you want to achieve.
If all you need is to load data from one table to another without any transformations, you can do one of the following:
If your tables reside in 2 different databases on the same server, you can use a tMysqlRow and execute a query "INSERT INTO catalog.table SELECT * from catalog2.table2..". You can do some simple transformations in SQL if needed.
If your tables live in different servers, check the generic solution I suggested for a similar question here. It may need some tweaking depending on your use case, but the general idea is to replicate the functionality of INSERT INTO SELECT when the tables are not on the same server.
I have around 25 tables to load to target with same structure and which use the same logic for loading. I have prepared one job which does that, but it's a long process to design all the tables.
Is there any way to pass the table name and load to target, basically a small job (in size).
I am using Talend open studio.
Check my answer to a similar question where I proposed a generic solution for loading a MySQL table to another MySQL table.
You just need to modify the queries that retrieve the tables' metadata (columns) depending on your database type.
I'm trying to use tELTPostgresqlOutput with postgres 9.3 server and this is the result:
With a simple tPostgresqlInput and a tLogRow it works perfectly.
This is not how to use the ELT components. These should be used to do in database server transformations such as creating a star schema table from multiple tables in the same database. This allows you to use the database to do the transformation and avoid reading the data into memory for your job. It's particularly useful when dealing with large datasets that can't be broken down for the transformation.
If you want to transfer data from one database server/vendor to another you will need to use ETL components (pretty much anything not explicitly marked ELT) to read data out of the source database and write it back to the target database.
In this case you should be using a tMSSQLInput component to read in the data you need, a tMap to transform the data in the way you want and a tPostgresqlOutput component to write the data out to the Postgres database.
Is there any tool to quickly convert a DB2 table rows into collection of XML documents that we can load to Marklogic?
DB2 supports the SQL/XML publishing extensions that were introduced in SQL:2003. These functions include XMLSERIALIZE, XMLELEMENT, XMLATTRIBUTE, and XMLFOREST, and are easily added to a SQL SELECT statement to produce a simple, well-formed XML document for each row in the result set. By writing queries that retrieve the table names and column layouts from DB2's catalog views, it is possible to automate the creation of the XML-publishing SELECT statements for a large number of tables.
One way of doing this would be to use the MLSQL toolkit ( http://developer.marklogic.com/code/mlsql ). It allows accessing relational databases from within your XQuery code in MarkLogic. Not sure how the returned data actually looks like, but it should be easy to process it within XQuery, and insert your data as XML into MarkLogic.
Just make sure not to try to load a million records in one statement, but instead try to spawn batches of lets say 1000 records at a time. Spawning will also allow for handling it with multiple threads, so should be faster for that reason too..
HTH!
Do you need to stream from DB2 to MarkLogic? Or can you temporarily dump all the documents to an intermediary filesystem and then read them in? If you can dump, then simply use some DB2 tooling (like #Fred's answer above) to export the rows to a bunch of XML documenets in a filesystem and use one of many methods for reading in a directory full of XML files into MarkLogic (like Information Studio (UI or apis), RecordLoader, and so on).
If you have don't want to store them in the filesystem as an intermediary, then you could write an InformationStudio plugin for MarkLogic that will pull out each row and insert a document into MarkLogic. You'd like need some web-service or rest endpoint that the plugin could call to extract the document data from DB2.
Alternatively, I suspect you could use the DB2 tooling (described by #Fred) that will let you execute some code per row of your table. If you can do that in Java (or .Net), then pull in the MarkLogic XCC APIs which will give you the ability to write documents into MarkLogic.