SELECT Query fails because of restrictions or so it says [duplicate] - mysql

Question

This question already has answers here:
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints
(26 answers)
Closed 5 years ago.
I'm running a query against a MySQL database, and its statement is simply
SELECT * FROM tableOperationsHistory;
However, it fails and I get this exception (I translated it into English):
Fail activating restrictions. One or more rows contain values that
violate non-null, unique or foreign-key restrictions.
This is the routine where the error happens:
Public Function RetrieveTable(ByVal command_text As String, Optional ByVal parameters As ParameterSet = Nothing) As DataTable
Dim dt As New DataTable, retry = False
Do
Using comm = conn.CreateCommand
comm.CommandText = command_text
If parameters IsNot Nothing Then
Dim par As DbParameter
For Each pair In parameters
par = comm.CreateParameter
par.ParameterName = pair.Key
par.Value = pair.Value
comm.Parameters.Add(par)
Next
End If
Dim rdr As DbDataReader
RequestConnection()
Try
rdr = comm.ExecuteReader
dt.Load(rdr)
retry = False
Catch ex As Exception
retry = ShouldRetry(ex) 'EXCEPTION IS CAUGHT HERE
End Try
DismissConnection()
End Using
Loop While retry
Return dt
End Function
And this is the table definition statement:
CREATE TABLE `tableOperationsHistory` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`numero` varchar(45) DEFAULT NULL,
`pasta_id` int(11) DEFAULT NULL,
`dataHoraInicioPrazo` datetime DEFAULT NULL,
`dataHoraFinalPrazo` datetime DEFAULT NULL,
`urgente` tinyint(4) DEFAULT NULL,
`setorOrigem_id` int(11) DEFAULT NULL,
`unidade_id` int(11) DEFAULT NULL,
`setor_id` int(11) DEFAULT NULL,
`usuario_id` int(11) DEFAULT NULL,
`modalidadeComunicacaoJudicial_id` int(11) DEFAULT NULL,
`modalidadeRepercussao_id` int(11) DEFAULT NULL,
`especieTarefa_id` int(11) DEFAULT NULL,
`postIt` varchar(255) DEFAULT NULL,
`teor_observacao` varchar(255) DEFAULT NULL,
`comunicacaoJudicial_id` int(11) DEFAULT NULL,
`tarefa_id` int(11) DEFAULT NULL,
`mensagens` text,
`criadoPor_id` int(11) DEFAULT NULL,
`criadoEm` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=92 DEFAULT CHARSET=latin1;
How can this happen in a SELECT statement? What should I do?

Answer 1

This great community helped me to realize that such an error can be caused by "a mismatch in column definition (e.g. size of char fields) between the database and the dataset", and pointed me to another thread: https://stackoverflow.com/a/7029713/3718031
Possible relation with this, too: Column longtext exceeds the MaxLength limit
In my case, there are columns with "TEXT" datatype and it seems that might be the problem.
I thank deeply to all those who commented in my question and helped me to learn this.
EDIT: Since this question was voted-to-close and my problem remained, I tried to investigate a little further and made another question, I hope that one is properly exposed.