Failed to enable constraints. One or more rows con

Question

I make an outer join and executed successfully in the informix database but I get the following exception in my code:

DataTable dt = TeachingLoadDAL.GetCoursesWithEvalState(i, bat);

Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.

I know the problem, but I don't know how to fix it.

The second table I make the outer join on contains a composite primary key which are null in the previous outer join query.

EDIT:

    SELECT UNIQUE a.crs_e,  a.crs_e  || '/ ' || a.crst crs_name, b.period,
           b.crscls, c.crsday, c.from_lect, c.to_lect,
           c.to_lect - c.from_lect + 1 Subtraction, c.lect_kind, e.eval, e.batch_no,
           e.crsnum, e.lect_code, e.prof_course
    FROM rlm1course a, rfc14crsgrp b, ckj1table c, mnltablelectev d,
         OUTER(cc1assiscrseval e)  
    WHERE a.crsnum = b.crsnum 
    AND b.crsnum = c.crsnum 
    AND b.crscls = c.crscls 
    AND b.batch_no = c.batch_no 
    AND c.serial_key = d.serial_key  
    AND c.crsnum = e.crsnum  
    AND c.batch_no = e.batch_no  
    AND d.lect_code= e.lect_code 
    AND d.lect_code = .... 
    AND b.batch_no = ....

The problem happens with the table cc1assiscrseval. The primary key is (batch_no, crsnum, lect_code).

How to fix this problem?

---

EDIT:

According to @PaulStock advice: I do what he said, and i get:

? dt.GetErrors()[0] {System.Data.DataRow} HasErrors: true ItemArray: {object[10]} RowError: "Column 'eval' does not allow DBNull.Value."

So I solve my problem by replacing e.eval to ,NVL (e.eval,'') eval.and this solves my problem. Thanks a lot.

Answer 1

You can disable the constraints on the dataset. It will allow you to identify bad data and help resolve the issue.

e.g.

dataset.TableA.Clear();
dataset.EnforceConstraints = false;
dataAdapter1.daTableA.Fill(dataset, TableA");

The fill method might be slightly different for you.

Answer 2

This worked for me, source: here

I had this error and it wasn't related with the DB constrains (at least in my case). I have an .xsd file with a GetRecord query that returns a group of records. One of the columns of that table was "nvarchar(512)" and in the middle of the project I needed to changed it to "nvarchar(MAX)".

Everything worked fine until the user entered more than 512 on that field and we begin to get the famous error message "Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints."

Solution: Check all the MaxLength property of the columns in your DataTable.

The column that I changed from "nvarchar(512)" to "nvarchar(MAX)" still had the 512 value on the MaxLength property so I changed to "-1" and it works!!.

Answer 3

I solved this problem by doing the "subselect" like it:

string newQuery = "select * from (" + query + ") as temp";

When do it on mysql, all collunms properties (unique, non-null ...) will be cleared.

Answer 4

The problem is with the Data Access designer. In Visual Studio, When we pull a View from "Server Explorer" to the Designer window, it is adding either a Primary key on a column randomly or marking something to a NOT NULL though it is actually set to null. Though the actual View creation in the SQL db server, doesn't have any primary key defined or the NOT NULL defined, the VS designer is adding this Key/constraint.

You can see this in the designer - it is shown with a key icon on left of the column name.

Solution: Right click on the key icon and select 'Delete Key'. This should solve the problem. You can also right click on a column and select "Properties" to see the list of properties of a column in the VS Data access designer and change the values appropriately.

Answer 5

Mine started working when I set AllowDBNull to True on a date field on a data table in the xsd file.

Answer 6

I solved the same problem by changing this from false to true. in the end I went into the database and changed my bit field to allow null, and then refreshed my xsd, and refreshed my wsdl and reference.cs and now all is well.

this.columnAttachPDFToEmailFlag.AllowDBNull = true;