Enterprise Architect - how to extract nullability of a database table column?

Question

I have a database table defined in EA. In this table I have a column where NULL is allowed. When I use a script or an API to extract nullability from this column, I understand this should be done using the LowerBound and UpperBound values. When LowerBound is 0, it is a nullable field, if it is 1, NULL is not allowed.

However, when I set the NULL field, LowerBound is still 1, as noted on the following picture:

How can I correctly extract nullability from a database column?

Where from did you get that wisdom that `lowerbound == 0` means nullable?? — qwerty_so, Sep 14 '19 at 18:06

score 0 · Answer 1 · answered Sep 09 '19 at 16:32

0

You have to look into Attribute.AllowDuplicates or t_attribute.AllowDuplicates (well, it's EA).

answered Sep 09 '19 at 16:32

qwerty_so

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score 0 · Answer 2 · edited Sep 18 '19 at 15:56

There seem to be two ways of retrieving that information:

Via SQL
Via API

Extending your example I defined to additional columns: NotNullAttribute and NullAttribute as shown in the figure below:

Now you get the results shown below when querying the element and its attributes:

LINQ and SQL query showing nullable columns:

SELECT *
FROM
  [t_attribute] [t]
WHERE
  [t].[Name] LIKE '%NullAttribute%'

Script for showing database table columns attributes:

function main(id)
{
    var element AS EA.Element;
    element = Repository.GetElementByID(id);

    var attributes AS EA.Collection;
    attributes = element.Attributes;
    for(var c = 0; c < attributes.Count; c++)
    {
        var attribute AS EA.Attribute;
        attribute = attributes.GetAt(c);

        Session.Output(attribute.Name + ": " + attribute.AllowDuplicates);
    }
}

main(18365);

// Output
/*
Id: true    
Name: false 
CustomerTypeEnumId: true    
NotNullAttribute: true  
NullAttribute: false    
*/

Enterprise Architect - how to extract nullability of a database table column?

2 Answers2