I have a fairly simple CSV file that I would like to use within a SQL query. I'm using Oracle SQL Developer but none of the solutions I have found on the web so far seem to have worked. I don't need to store the data (unless I can use temp tables?) just to query it and show results.
Thank You!
You need to create an EXTERNAL TABLE. This essentially maps a CSV (or indeed any flat file) to a table. You can then use that table in queries. You will not be able to perform DML on the external table.
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I am still learning Oracle SQL, and I've been trying to find the best way to update/insert records in an OracleSQL table with the data from a CSV file.
So far, I've figured out how to load the csv into a temporary table using External Tables in Oracle, but I'm having difficulty finding a detailed guide on how to update/insert (UPSERT) the loaded data into an existing table.
What is the best way to do this, when I have 30+ fields in the table? For example, is it best to read the csv line by line with something like pandas and update each record one by one, or is it best to do it with a sql script using something like a merge statement? Not all records in the csv have a value for the primary key, in which case I need to insert rather than update. Thanks for the help!
That looks like a MERGE, indeed.
Data from external table would then be used to
update values in existing rows
create new rows in the target table
Pandas and row-by-row processing? I wouldn't do that. If you already have a powerful database, then use its capabilities. Row-by-row is usually slow-by-slow and there's rarely some benefit in doing it that way.
Can anyone help on how to convert hana sql tables to .hdb tables and use them? For converting into .hdb files at first I have imported table .csv format and after this I am not sure how to convert to .hdb table. can someone provide any process
I'm not really sure what you going for but using hdb tables is as easy as creating table_name.hdb in exactly the same format (I.E. COLUMN TABLE ... ) as it was created in "classic" schema. Help Sap hdbtables
You can use the SAP HANA developer CLI's massConvert functionality to convert one or more tables to hdbtable.
Note that this will only take care of the table structure. If you have data that you want to keep you will have to copy it manually, for example, via a CSV export/import.
I have a very large data set in GPDB from which I need to extract close to 3.5 million records. I use this for a flatfile which is then used to load to different tables. I use Talend, and do a select * from table using the tgreenpluminput component and feed that to a tfileoutputdelimited. However due to the very large volume of the file, I run out of memory while executing it on the Talend server.
I lack the permissions of a super user and unable to do a \copy to output it to a csv file. I think something like a do while or a tloop with more limited number of rows might work for me. But my table doesnt have any row_id or uid to distinguish the rows.
Please help me with suggestions how to solve this. Appreciate any ideas. Thanks!
If your requirement is to load data into different tables from one table, then you do not need to go for load into file and then from file to table.
There is a component named tGreenplumRow which allows you to write direct sql queries (DDL and DML queries) in it.
Below is a sample job,
If you notice, there are three insert statements inside this component. It will be executed one by one separated by semicolon.
I have about 30 files that will need to be exported from one sql table. What I have now is creating a sql table for each file, then exporting the contents of that individual table. This works fine but I really didn't want to have 30 tables on the server. Is there a way to export from one table using 30 different sql queries?
Thanks in advance
This really depends on your data need and how complicated the export is but... generally people do not create an export table per export. Data Transform Task's source can be a table (which you are currently using) or a stored procedure or a view.
I would need to know more about your structure to advise more accurately but... one table per export is definitely not the best solution.
I would use a parameterized stored procedure if possible.
How do I copy data from multiple tables within one database to another database residing on a different server?
Is this possible through a BTEQ Script in Teradata?
If so, provide a sample.
If not, are there other options to do this other than using a flat-file?
This is not possible using BTEQ since you have mentioned both the databases are residing in different servers.
There are two solutions for this.
Arcmain - You need to use Arcmain Backup first, which creates files containing data from your tables. Then you need to use Arcmain restore which restores the data from the files
TPT - Teradata Parallel Transporter. This is a very advanced tool. This does not create any files like Arcmain. It directly moves the data between two teradata servers.(Wikipedia)
If I am understanding your question, you want to move a set of tables from one DB to another.
You can use the following syntax in a BTEQ Script to copy the tables and data:
CREATE TABLE <NewDB>.<NewTable> AS <OldDB>.<OldTable> WITH DATA AND STATS;
Or just the table structures:
CREATE TABLE <NewDB>.<NewTable> AS <OldDB>.<OldTable> WITH NO DATA AND NO STATS;
If you get real savvy you can create a BTEQ script that dynamically builds the above statement in a SELECT statement, exports the results, then in turn runs the newly exported file all within a single BTEQ script.
There are a bunch of other options that you can do with CREATE TABLE <...> AS <...>;. You would be best served reviewing the Teradata Manuals for more details.
There are a few more options which will allow you to copy from one table to another.
Possibly the simplest way would be to write a smallish program which uses one of their communication layers (ODBC, .NET Data Provider, JDBC, cli, etc.) and use that to take a select statement and an insert statement. This would require some work, but it would have less overhead than trying to learn how to write TPT scripts. You would not need any 'DBA' permissions to write your own.
Teradata also sells other applications which hides the complexity of some of the tools. Teradata Data Mover handles provides an abstraction layer between tools like arcmain and tpt. Access to this tool is most likely restricted to DBA types.
If you want to move data from one server to another server then
We can do this with the flat file.
First we have fetch data from source table to flat file through any utility such as bteq or fastexport.
then we can load this data into target table with the help of mload,fastload or bteq scripts.