[odb-users] Null values for unset properties

Rafael Pena pena.rd at gmail.com
Mon Jul 25 13:24:02 EDT 2011

I have a class as below. Is there anyway that I can keep the two optional
fields (double optionalValue, string optionalString) as null? If I don't set
the optionValue it defaults to 0 and optionalString defaults to "". I know
the queries can use is_null operator so I am guessing it can be changed
somehow. NOT NULL is the default type in ddl generated by ODB, can I change
the optional fields to #pragma db type("DOUBLE")?  Is there a way to leave
unset fields as null?

#pragma db object
class File {
    File() {
    File(const string& filename);
    File(const File& orig);
    virtual ~File();
//Setters and Getters

    friend class odb::access;
#pragma db id auto
    unsigned long fileId;

    string filename;
    string fileType;
    ptime fileDate;
    ptime converterStartdate;
    ptime converterEndDate;
    string loadingHost;
    unsigned long fileSize;

    #pragma db type("DOUBLE")  // Can I do this?
    double optionalValue;
    string optionalString;


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