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How to insert a null value into a database record


How to insert a null value into a field?

When I try to insert null, I get 0.


OutSystems Platform always assumes default values for the built-in types.

The built-in actions to create and/or update the database write values to the database, unless the attribute is a foreign key. To avoid problems with constraints, foreign keys are stored as null if not defined. But an undefined decimal is written as 0.

Use a SQL node to save nulls to the database. You can build code generic enough for different DBMS and avoid having business logic inside the query.

In the example below, a SQL node has two inputs. ActivityNotes is a text input with the property Expand Inline defined to yes. This means that the value of ActivityNotes input will be injected directly into the query.

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To pass data to the query parameter ActivityNodes, check if the value:

  • If empty, pass the string "null".
  • Otherwise, pass the value encoded as SQL.

Use EncodeSql() to avoid SQL injection on query parameters with Expand Inline.


This way you can build the code generic enough for different DBMS, and you are avoiding business logic inside the query.

More information:

Available data types
Defines the default values for each type.
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