Help Center/ Data Lake Insight/ FAQs/ Datasource Connections/ Datasource Connection O&M/ A Null Value Is Written Into a Non-Null Field When a DLI Datasource Connection Is Used to Connect to a GaussDB(DWS) Table
Updated on 2023-03-21 GMT+08:00
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A Null Value Is Written Into a Non-Null Field When a DLI Datasource Connection Is Used to Connect to a GaussDB(DWS) Table

Symptom

A table was created on GaussDB(DWS) and then a datasource connection was created on DLI to read and write data. An error message was displayed during data writing, indicating that DLI was writing a null value to a non-null field of the table, and the job failed.

The error message is as follows: 
DLI.0999: PSQLException: ERROR: dn_6009_6010: null value in column "ctr" violates not-null constraint
Detail: Failing row contains (400070309, 9.00, 25, null, 2020-09-22, 2020-09-23 04:30:01.741).

Cause Analysis

  1. The CIR field in the source table is of the DOUBLE type.
    Figure 1 Creation statement of the source table
  2. The field type in the target table is DECIMAL(9,6).
    Figure 2 Creation statement of the target table
  3. View the source table data. The CTR value that causes the problem is 1675, which exceed the precision (9 – 6 = 3 digits) of the DECIMAL(9,6) type. A null value was generated when the double value was converted to the decimal value, and the insert operation failed.

Procedure

Change the precision of the decimal data defined in the target table.