Inserts a null value into the CLOB field in the Oracle database

The ORA-01084 invalid argument in OCI call error is always reported when data is inserted into the Oracle database because one of the field types in the table is CLOB and can be empty when the error is thrown when a null value is inserted into the field. Later, if you decide whether to use DBNull.Value for null values, this resolves the problem.

Null refers to an invalid object reference, whereas DBNull is a class, and DBNull.Value is its only instance. An instance of DBNull DBNull.Value is the representation of empty data in a database table in. Net code. We know that when a nullable field in a database table is not assigned a value, the field in the database table is specified as NULL, so what does this null value say in. Net code, which is DBNull. Value. Conversely, in code, when the value of a field equals DBNull. Value, it means that this field holds null in the database, meaning its value in the database is null. Therefore, the DBNull.Value object points to a valid object, not as null does not point to any valid object.

DBNull is a separate class, which means that the class can only exist for this instance.

If the data for the database field is missing, you can use DBNull. The Value property explicitly assigns DBNull object values to the field. However, most data providers are assigned automatically.

To calculate a database field to determine whether its value is DBNull, you can pass the field value toDBNull.Value.EqualsMethod.convert. IsDBNull method, the datatablereader. IsDBNull method, the idatarecord. IsDBNull method, and several other methods. " These methods include Visual Basic's IsDBNull function, Convert.isdbnull method, Datatablereader.isdbnull method, Idatarecord.isdbnull methods and several other methods.

dbnull, you can pass the field value to the Strong>dbnull.value.equals method. > example

The following example calls the DBNull.Value.Equals method to determine whether a database field in the contact database has a valid value. If there is a valid value, the field value is appended to the string that is output in the label.

Private voidoutputlabels (DataTable dt) {stringlabel; //Iterate rows of table   foreach(DataRow rowinchdt. Rows) {intLabellen; Label=String.Empty; Label+ = addfieldvalue (label, Row,"Title"); Label+ = addfieldvalue (label, Row,"FirstName"); Label+ = addfieldvalue (label, Row,"middleinitial"); Label+ = addfieldvalue (label, Row,"LastName"); Label+ = addfieldvalue (label, Row,"Suffix"); Label+="\ n"; Label+ = addfieldvalue (label, Row,"Address1"); Label+ = addfieldvalue (label, Row,"Aptno"); Label+="\ n"; Labellen=label.      Length; Label+ = addfieldvalue (label, Row,"Address2"); if(label. Length! =labellen) Label+="\ n"; Label+ = addfieldvalue (label, Row," City"); Label+ = addfieldvalue (label, Row," State"); Label+ = addfieldvalue (label, Row,"Zip");      Console.WriteLine (label);   Console.WriteLine (); }}Private stringAddfieldvalue (stringlabel, DataRow Row,stringfieldName) {                                   if(!DBNull.Value.Equals (Row[fieldname]))return(string) Row[fieldname] +" "; Else      returnString.Empty;}

Insert a null value for the CLOB field in the Oracle database