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Posted to issues@hop.apache.org by "dav-git-ide (via GitHub)" <gi...@apache.org> on 2026/09/01 08:20:31 UTC

[I] [Bug]: Generic Database maps SAP HANA VARBINARY columns to java.sql.Blob instead of byte[] (hop)

dav-git-ide opened a new issue, #8207:
URL: https://github.com/apache/hop/issues/8207

   ### Apache Hop version?
   
   2.19
   
   ### Java version?
   
   open jdk 21
   
   ### Operating system
   
   Windows
   
   ### What happened?
   
   When using a Generic Database connection with the SAP HANA JDBC driver, Apache Hop fails when reading VARBINARY columns.
   
   A query such as:
   
   SELECT *
   FROM MARA
   
   is successfully executed by SAP HANA, but Hop fails while reading the ResultSet with:
   
   Unable to get value 'Binary' from database resultset
   SAP DBTech JDBC: Cannot convert SQL type VARBINARY to Java type java.sql.Blob.
   
   The failing column is exposed by SAP HANA JDBC as VARBINARY.
   
   According to the SAP HANA JDBC documentation, VARBINARY should be handled as binary byte data, while BLOB is mapped to java.sql.Blob.
   
   It appears that Hop Generic Database maps the VARBINARY column to Hop Binary and then retrieves it using java.sql.Blob handling instead of byte[] / ResultSet.getBytes().
   
   Steps to Reproduce
   
   1. Install the SAP HANA JDBC driver (ngdbc.jar) in Apache Hop.
   2. Create a Relational Database Connection using "Generic database".
   3. Configure:
   
      Driver class:
      com.sap.db.jdbc.Driver
   
      JDBC URL:
      jdbc:sap://<host>:<port>
   
   4. Test the connection successfully.
   5. Create a pipeline with a Table Input transform.
   6. Run a query against a table containing a VARBINARY column, for example:
   
      SELECT *
      FROM MARA
   
   7. Preview or execute the pipeline.
   8. Hop starts reading the ResultSet but fails when it reaches the VARBINARY column.
   
   Observed error:
   
   Unable to get value 'Binary' from database resultset, index 189
   
   SAP DBTech JDBC:
   Cannot convert SQL type VARBINARY to Java type java.sql.Blob.
   
   Expected Behavior
   
   VARBINARY columns returned by the SAP HANA JDBC driver should be read as binary byte data, for example using ResultSet.getBytes() / byte[] handling.
   
   A VARBINARY column should not be requested from the JDBC driver as java.sql.Blob.
   
   Queries containing VARBINARY columns should therefore be readable through a Generic Database connection without requiring the user to exclude or cast those columns manually.
   
   Additional Information / Possible Cause
   
   The issue appears to be in the generic JDBC type handling.
   
   SAP HANA JDBC distinguishes between:
   
   VARBINARY -> binary byte data
   BLOB      -> java.sql.Blob
   
   However, Hop reports the VARBINARY column as Hop type "Binary" and appears to retrieve it using Blob handling.
   
   This causes the SAP HANA JDBC driver to reject the conversion:
   
   Cannot convert SQL type VARBINARY to Java type java.sql.Blob.
   
   A possible fix would be to distinguish JDBC Types.VARBINARY / BINARY / LONGVARBINARY from Types.BLOB when retrieving values from the ResultSet.
   
   For VARBINARY/BINARY types, ResultSet.getBytes() or equivalent byte[] handling would seem more appropriate.
   
   Additional Context / References
   
   SAP HANA JDBC documentation:
   https://help.sap.com/docs/SAP_HANA_CLIENT/f1b440ded6144a54ada97ff95dac7adf/109397c2206a4ab2a5386d494f4cf75e.html?locale=en-US
   
   
   
   
   ### Issue Priority
   
   Priority: 0
   
   ### Issue Component
   
   Component: Transforms, Component: Database


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Re: [I] [Bug]: Generic Database maps SAP HANA VARBINARY columns to java.sql.Blob instead of byte[] (hop)

Posted by "hansva (via GitHub)" <gi...@apache.org>.
hansva commented on issue #8207:
URL: https://github.com/apache/hop/issues/8207#issuecomment-5491186975

   .take-issue


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Re: [I] [Bug]: Generic Database maps SAP HANA VARBINARY columns to java.sql.Blob instead of byte[] (hop)

Posted by "hansva (via GitHub)" <gi...@apache.org>.
hansva closed issue #8207: [Bug]: Generic Database maps SAP HANA VARBINARY columns to java.sql.Blob instead of byte[]
URL: https://github.com/apache/hop/issues/8207


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