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Ivannava
Asked: 2022-06-04 13:38:09 +0800 CST 2022-06-04 13:38:09 +0800 CST

How to add a blob data type column with an empty default value in hana

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I'm trying to add a column to a Hana sql table of blob data type, but my table already contains data and must not be null, which prevents me from adding the column. Does anyone know the correct structure.

I am doing it like this:

ALTER TABLE "CLIENTES"."DATOS" ADD ("IMAGEN" BLOB NOT NULL DEFAULT)

It is the one that gives me an error, can someone help me

mysql

2 Answers

  1. Best Answer

    This happens because the table already has rows. There are two paths.

    1. Check if you can useALTER TABLE "CLIENTES"."DATOS" ADD ("IMAGEN" BLOB NOT NULL NOVALIDATE )
    2. If you don't succeed, then the correct thing to do would be to first alter the table like this ALTER TABLE "CLIENTES"."DATOS" ADD ("IMAGEN" BLOB), then assign a value to the data that the table already has, for this you use the UPDATE function with a SET in the IMAGE column, once all the fields already have a value other than NULL, add the not null constraint again for this column using ALTER TABLE | ALTER COLUMNand add the constraint.
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  2. Initialize with an empty BLOB:

    ALTER TABLE "CLIENTES"."DATOS" 
  ADD ("IMAGEN" BLOB NOT NULL DEFAULT EMPTY_BLOB())
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