I have an SQL statement that I'm executing through OleDb, the statement is something like this:
INSERT INTO mytable (name, dept) VALUES (#name, #dept);
I'm adding parameters to the OleDbCommand like this:
OleDbCommand Command = new OleDbCommand();
Command.Connection = Connection;
OleDbParameter Parameter1 = new OleDbParameter();
Parameter1.OleDbType = OleDbType.VarChar;
Parameter1.ParamterName = "#name";
Parameter1.Value = "Bob";
OleDbParameter Parameter2 = new OleDbParameter();
Parameter2.OleDbType = OleDbType.VarChar;
Parameter2.ParamterName = "#dept";
Parameter2.Value = "ADept";
Command.Parameters.Add(Parameter1);
Command.Parameters.Add(Parameter2);
The problem I've got is, if I add the parameters to command the other way round, then the columns are populated with the wrong values (i.e. name is in the dept column and vice versa)
Command.Parameters.Add(Parameter2);
Command.Parameters.Add(Parameter1);
My question is, what is the point of the parameter names if parameters values are just inserted into the table in the order they are added command? The parameter names seems redundant?
The Problem is that OleDb (and Odbc too) does not support named parameters.
It only supports what's called positional parameters.
In other words: The name you give a parameter when adding it to the commands parameters list does not matter. It's only used internally by the OleDbCommand class so it can distinguish and reference the parameters.
What matters is the order in which you add the parameters to the list. It must be the same order as the parameters are referenced in the SQL statement via the question mark character (?).
But here is a solution that allows you to use named parameters in the SQL statement. It basically replaces all parameter references in the SQL statement with question marks and reorders the parameters list accordingly.
It works the same way for the OdbcCommand class, you just need to replace "OleDb" with "Odbc" in the code.
Use the code like this:
command.CommandText = "SELECT * FROM Contact WHERE FirstName = #FirstName";
command.Parameters.AddWithValue("#FirstName", "Mike");
command.ConvertNamedParametersToPositionalParameters();
And here is the code
public static class OleDbCommandExtensions
{
public static void ConvertNamedParametersToPositionalParameters(this OleDbCommand command)
{
//1. Find all occurrences of parameter references in the SQL statement (such as #MyParameter).
//2. Find the corresponding parameter in the commands parameters list.
//3. Add the found parameter to the newParameters list and replace the parameter reference in the SQL with a question mark (?).
//4. Replace the commands parameters list with the newParameters list.
var newParameters = new List<OleDbParameter>();
command.CommandText = Regex.Replace(command.CommandText, "(#\\w*)", match =>
{
var parameter = command.Parameters.OfType<OleDbParameter>().FirstOrDefault(a => a.ParameterName == match.Groups[1].Value);
if (parameter != null)
{
var parameterIndex = newParameters.Count;
var newParameter = command.CreateParameter();
newParameter.OleDbType = parameter.OleDbType;
newParameter.ParameterName = "#parameter" + parameterIndex.ToString();
newParameter.Value = parameter.Value;
newParameters.Add(newParameter);
}
return "?";
});
command.Parameters.Clear();
command.Parameters.AddRange(newParameters.ToArray());
}
}
Parameter NAMES are generic in the SQL support system (i.e. not OleDb specific). Pretty much ONLY OleDb / Odbc do NOT use them. They are there because OleDb is a specific implementation of the generic base classes.
I'm trying to save a PDF file into my database table is there any proper way to do this. I am working with C++/CLI.
I have tried this code below but I am getting System.byte[] instead of actual value
FileStream^ fs = gcnew FileStream("E:\\test.pdf",FileMode::Open,FileAccess::Read);
BinaryReader^ br=gcnew BinaryReader(fs);
cli::array<System::Byte>^ Mybuffer=gcnew cli::array<System::Byte>(fs->Length);
Mybuffer =br->ReadBytes(Convert::ToInt32(fs->Length));
SqlCommand^ cmd = gcnew SqlCommand
("Insert Into Employees(empName,branchGuid,cvFile) values ('" + textBox1->Text + "',(select branchGuid from Branches where branchName='" + branchesComboBox->SelectedValue->ToString() + "')," + Mybuffer +");", conn);
SqlDataAdapter^ sda = gcnew SqlDataAdapter(cmd);
DataSet^ ds = gcnew DataSet();
sda->Fill(ds, "insert");
The issue is where you're concatenating the buffer into the SQL command.
+ Mybuffer +");"
Mybuffer is of type array<Byte>^. When you do the string concatenation on something other than a string, it calls ToString(). The .Net array class doesn't output the array contents when ToString is called, it just does the default behavior, which is to output the class name (In C# format, so [] instead of array<>).
You haven't said how the cvFile field of the Employees table is defined. You'll need to either iterate over the byte array and create the SQL statement with the value of all the bytes, or you may need to use some other API to insert the data. If it's a BLOB type, see this answer, there's a lot of good concepts there: How to insert BLOB datatype
I am wondering how to insert an image on one of the fields in my postgresql table. I cannot find an appropriate tutorial re this matter. The dataype of the field is oid. Has anyone tried this? Thanks!
// All LargeObject API calls must be within a transaction
conn.setAutoCommit(false);
// Get the Large Object Manager to perform operations with
LargeObjectManager lobj = ((org.postgresql.PGConnection)conn).getLargeObjectAPI();
//create a new large object
int oid = lobj.create(LargeObjectManager.READ | LargeObjectManager.WRITE);
//open the large object for write
LargeObject obj = lobj.open(oid, LargeObjectManager.WRITE);
// Now open the file
File file = new File("myimage.gif");
FileInputStream fis = new FileInputStream(file);
// copy the data from the file to the large object
byte buf[] = new byte[2048];
int s, tl = 0;
while ((s = fis.read(buf, 0, 2048)) > 0)
{
obj.write(buf, 0, s);
tl += s;
}
// Close the large object
obj.close();
//Now insert the row into imagesLO
PreparedStatement ps = conn.prepareStatement("INSERT INTO imagesLO VALUES (?, ?)");
ps.setString(1, file.getName());
ps.setInt(2, oid);
ps.executeUpdate();
ps.close();
fis.close();
Found that sample code from here. Really very good bunch of sql operations.
To quote this site,
PostgreSQL database has a special data type to store binary data
called bytea. This is a non-standard data type. The standard data type
in databases is BLOB.
You need to write a client to read the image file, for example
File img = new File("woman.jpg");
fin = new FileInputStream(img);
con = DriverManager.getConnection(url, user, password);
pst = con.prepareStatement("INSERT INTO images(data) VALUES(?)");
pst.setBinaryStream(1, fin, (int) img.length());
pst.executeUpdate();
You can either use the bytea type or the large objects facility. However note that depending on your use case it might not be a good idea to put your images in the DB because of additional load it may put on the DB server.
Rereading your question I notice you mentioned you have a field of type oid. If this is an application you are modifying it suggests to me it is using large objects. These objects get an oid which you then need to store in another table to keep track of them.
This question is related to another one I posted earlier.
To recap, I need to fix an issue with an ancient legacy app where people messed up data storage by re-installing the software the wrong way.
The application stores data by saving a record in an SQL DB. Each record holds a reference to a file on disk of which the filename auto-increments.
By re-installing the app the filename auto-increment was re-set so the DB now holds multiple unrelated records which reference the same filename and I have to directories with files which I obviously cannot merge because of these identical filenames. The files hold no reference to the DB data so the only course of action that remains is to filter the DB records on date created and try to rename "EXED" to "IXED" or something like that.
The DB is relatively simple with one table containing a column that holds data of type "Image".
An example content of this image data is as follows:
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
The data is apparently Hex which mostly encodes meaningless crap but also holds the name of physical files (towards the end of the data field) in the filesystem that is linked to the SQL records:
??#7???????????EXED48bb?-P??????Dyspnoe??P??????VELD RAMP 360
I'm interested in the EXED part.
There is no clear regularity in the offset at which the filename appears and the filename is of variable length (so I do not know beforehand how long the substring will be).
I can call up all records with SQL like this:
SELECT COUNT(*) as "Number of EXED Files after critical date"
FROM [ZAN].[dbo].[zanu]
WHERE udata is not null
and SUBSTRING(udata, 1 , 2147483647) like '%EXED%'
and [udatum] > 0
and CONVERT(date,[udatum]) > CONVERT(date,'20100629')
What I would like to do now is know how to replace this EXED substring by something else (e.g. IXID).
I'm unfamiliar with SQL and Googling so far has yielded very little information on my options here.
I also have no other info on the original code that generated this data/the data format/encoding/whatever...
It's a mess really.
Any help is welcome!
An update on this:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Data.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Threading;
namespace ZANLinq
{
class Program
{
static void Main(string[] args)
{
try
{
DataContext zanDB = new DataContext(#"Data Source=.\,1433;database=ZAN;Integrated Security=true");
string strSQL = #"SELECT
Idnr,
Udatum,
Uzeit,
Unr,
Uart,
Ubediener,
Uzugriff,
Ugr,
Uflags,
Usize,
Udata
FROM Zanu
WHERE (Udata IS NOT null and SubString(Udata, 1 , 2147483647) LIKE '%EXED%')
AND (Idnr = ' 2')";
var zanQuery = zanDB.ExecuteQuery<Zanu>(strSQL);
List<Zanu> list = zanQuery.ToList<Zanu>();
foreach (Zanu zanTofix in list)
{
string strOriginal = ASCIIEncoding.ASCII.GetString(zanTofix.Udata);
string strFixed = strOriginal.Replace("EXED", "IXED");
zanTofix.Udata = ASCIIEncoding.ASCII.GetBytes(strFixed);
}
zanDB.SubmitChanges();
//Console.WriteLine(zanResults.Count<Zanu>().ToString());
}
catch (SqlException e)
{
Console.WriteLine(e.Message);
}
}
}
}
It finds the records I'm interested in, I can easily manipulate the data but the commit doesnt work. I'm stumped, there are no exceptions, no indication the code is wrong.
Anybody have ideas?
UPDATE:
I think the above does not work because my table appears to have a composite PK (I cannot change this):
Since I could not debug this (no info anywhere, no exceptions, just a silent fail of the submitchanges()) I decided to use another approach and abandon Linq2SQL altogether:
try
{
SqlConnection thisConnection = new SqlConnection(#"Network Library=DBMSSOCN;Data Source=.\,1433;database=ZAN;Integrated Security=SSPI");
DataSet zanDataSet = new DataSet();
SqlDataAdapter zanDa;
SqlCommandBuilder zanCmdBuilder;
thisConnection.Open();
//Initialize the SqlDataAdapter object by specifying a Select command
//that retrieves data from the sample table.
zanDa = new SqlDataAdapter(#"SELECT
Idnr,
Udatum,
Uzeit,
Unr,
Uart,
Ubediener,
Uzugriff,
Ugr,
Uflags,
Usize,
Udata
FROM Zanu
WHERE (Udata IS NOT null and SubString(Udata, 1 , 2147483647) LIKE '%IXED%')
AND (Idnr = ' 2')
AND (Uzeit = '13:21')", thisConnection);
//Initialize the SqlCommandBuilder object to automatically generate and initialize
//the UpdateCommand, InsertCommand, and DeleteCommand properties of the SqlDataAdapter.
zanCmdBuilder = new SqlCommandBuilder(zanDa);
//Populate the DataSet by running the Fill method of the SqlDataAdapter.
zanDa.Fill(zanDataSet, "Zanu");
Console.WriteLine("Records that will be affected: " + zanDataSet.Tables["Zanu"].Rows.Count.ToString());
foreach (DataRow record in zanDataSet.Tables["Zanu"].Rows)
{
string strOriginal = ASCIIEncoding.ASCII.GetString((byte[])record["Udata"]);
string strFixed = strOriginal.Replace("IXED", "EXED");
record["Udata"] = ASCIIEncoding.ASCII.GetBytes(strFixed);
//string strPostMod = ASCIIEncoding.ASCII.GetString((byte[])record["Udata"]);
}
zanDa.Update(zanDataSet, "Zanu");
thisConnection.Close();
Console.ReadLine();
}
catch (SqlException e)
{
Console.WriteLine(e.Message);
}
This seems to work but any input on why the Linq does not work and whether or not my second solution is efficient/optimal or not is still very much appreciated.
I am running data.bat file with the following lines:
Rem Tis batch file will populate tables
cd\program files\Microsoft SQL Server\MSSQL
osql -U sa -P Password -d MyBusiness -i c:\data.sql
The contents of the data.sql file is:
insert Customers
(CustomerID, CompanyName, Phone)
Values('101','Southwinds','19126602729')
There are 8 more similar lines for adding records.
When I run this with start > run > cmd > c:\data.bat, I get this error message:
1>2>3>4>5>....<1 row affected>
Msg 8152, Level 16, State 4, Server SP1001, Line 1
string or binary data would be truncated.
<1 row affected>
<1 row affected>
<1 row affected>
<1 row affected>
<1 row affected>
<1 row affected>
Also, I am a newbie obviously, but what do Level #, and state # mean, and how do I look up error messages such as the one above: 8152?
From #gmmastros's answer
Whenever you see the message....
string or binary data would be truncated
Think to yourself... The field is NOT big enough to hold my data.
Check the table structure for the customers table. I think you'll find that the length of one or more fields is NOT big enough to hold the data you are trying to insert. For example, if the Phone field is a varchar(8) field, and you try to put 11 characters in to it, you will get this error.
I had this issue although data length was shorter than the field length.
It turned out that the problem was having another log table (for audit trail), filled by a trigger on the main table, where the column size also had to be changed.
In one of the INSERT statements you are attempting to insert a too long string into a string (varchar or nvarchar) column.
If it's not obvious which INSERT is the offender by a mere look at the script, you could count the <1 row affected> lines that occur before the error message. The obtained number plus one gives you the statement number. In your case it seems to be the second INSERT that produces the error.
Just want to contribute with additional information: I had the same issue and it was because of the field wasn't big enough for the incoming data and this thread helped me to solve it (the top answer clarifies it all).
BUT it is very important to know what are the possible reasons that may cause it.
In my case i was creating the table with a field like this:
Select '' as Period, * From Transactions Into #NewTable
Therefore the field "Period" had a length of Zero and causing the Insert operations to fail. I changed it to "XXXXXX" that is the length of the incoming data and it now worked properly (because field now had a lentgh of 6).
I hope this help anyone with same issue :)
Some of your data cannot fit into your database column (small). It is not easy to find what is wrong. If you use C# and Linq2Sql, you can list the field which would be truncated:
First create helper class:
public class SqlTruncationExceptionWithDetails : ArgumentOutOfRangeException
{
public SqlTruncationExceptionWithDetails(System.Data.SqlClient.SqlException inner, DataContext context)
: base(inner.Message + " " + GetSqlTruncationExceptionWithDetailsString(context))
{
}
/// <summary>
/// PArt of code from following link
/// http://stackoverflow.com/questions/3666954/string-or-binary-data-would-be-truncated-linq-exception-cant-find-which-fiel
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
static string GetSqlTruncationExceptionWithDetailsString(DataContext context)
{
StringBuilder sb = new StringBuilder();
foreach (object update in context.GetChangeSet().Updates)
{
FindLongStrings(update, sb);
}
foreach (object insert in context.GetChangeSet().Inserts)
{
FindLongStrings(insert, sb);
}
return sb.ToString();
}
public static void FindLongStrings(object testObject, StringBuilder sb)
{
foreach (var propInfo in testObject.GetType().GetProperties())
{
foreach (System.Data.Linq.Mapping.ColumnAttribute attribute in propInfo.GetCustomAttributes(typeof(System.Data.Linq.Mapping.ColumnAttribute), true))
{
if (attribute.DbType.ToLower().Contains("varchar"))
{
string dbType = attribute.DbType.ToLower();
int numberStartIndex = dbType.IndexOf("varchar(") + 8;
int numberEndIndex = dbType.IndexOf(")", numberStartIndex);
string lengthString = dbType.Substring(numberStartIndex, (numberEndIndex - numberStartIndex));
int maxLength = 0;
int.TryParse(lengthString, out maxLength);
string currentValue = (string)propInfo.GetValue(testObject, null);
if (!string.IsNullOrEmpty(currentValue) && maxLength != 0 && currentValue.Length > maxLength)
{
//string is too long
sb.AppendLine(testObject.GetType().Name + "." + propInfo.Name + " " + currentValue + " Max: " + maxLength);
}
}
}
}
}
}
Then prepare the wrapper for SubmitChanges:
public static class DataContextExtensions
{
public static void SubmitChangesWithDetailException(this DataContext dataContext)
{
//http://stackoverflow.com/questions/3666954/string-or-binary-data-would-be-truncated-linq-exception-cant-find-which-fiel
try
{
//this can failed on data truncation
dataContext.SubmitChanges();
}
catch (SqlException sqlException) //when (sqlException.Message == "String or binary data would be truncated.")
{
if (sqlException.Message == "String or binary data would be truncated.") //only for EN windows - if you are running different window language, invoke the sqlException.getMessage on thread with EN culture
throw new SqlTruncationExceptionWithDetails(sqlException, dataContext);
else
throw;
}
}
}
Prepare global exception handler and log truncation details:
protected void Application_Error(object sender, EventArgs e)
{
Exception ex = Server.GetLastError();
string message = ex.Message;
//TODO - log to file
}
Finally use the code:
Datamodel.SubmitChangesWithDetailException();
Another situation in which you can get this error is the following:
I had the same error and the reason was that in an INSERT statement that received data from an UNION, the order of the columns was different from the original table. If you change the order in #table3 to a, b, c, you will fix the error.
select a, b, c into #table1
from #table0
insert into #table1
select a, b, c from #table2
union
select a, c, b from #table3
on sql server you can use SET ANSI_WARNINGS OFF like this:
using (SqlConnection conn = new SqlConnection("Data Source=XRAYGOAT\\SQLEXPRESS;Initial Catalog='Healthy Care';Integrated Security=True"))
{
conn.Open();
using (var trans = conn.BeginTransaction())
{
try
{
using cmd = new SqlCommand("", conn, trans))
{
cmd.CommandText = "SET ANSI_WARNINGS OFF";
cmd.ExecuteNonQuery();
cmd.CommandText = "YOUR INSERT HERE";
cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
cmd.CommandText = "SET ANSI_WARNINGS ON";
cmd.ExecuteNonQuery();
trans.Commit();
}
}
catch (Exception)
{
trans.Rollback();
}
}
conn.Close();
}
I had the same issue. The length of my column was too short.
What you can do is either increase the length or shorten the text you want to put in the database.
Also had this problem occurring on the web application surface.
Eventually found out that the same error message comes from the SQL update statement in the specific table.
Finally then figured out that the column definition in the relating history table(s) did not map the original table column length of nvarchar types in some specific cases.
I had the same problem, even after increasing the size of the problematic columns in the table.
tl;dr: The length of the matching columns in corresponding Table Types may also need to be increased.
In my case, the error was coming from the Data Export service in Microsoft Dynamics CRM, which allows CRM data to be synced to an SQL Server DB or Azure SQL DB.
After a lengthy investigation, I concluded that the Data Export service must be using Table-Valued Parameters:
You can use table-valued parameters to send multiple rows of data to a Transact-SQL statement or a routine, such as a stored procedure or function, without creating a temporary table or many parameters.
As you can see in the documentation above, Table Types are used to create the data ingestion procedure:
CREATE TYPE LocationTableType AS TABLE (...);
CREATE PROCEDURE dbo.usp_InsertProductionLocation
#TVP LocationTableType READONLY
Unfortunately, there is no way to alter a Table Type, so it has to be dropped & recreated entirely. Since my table has over 300 fields (😱), I created a query to facilitate the creation of the corresponding Table Type based on the table's columns definition (just replace [table_name] with your table's name):
SELECT 'CREATE TYPE [table_name]Type AS TABLE (' + STRING_AGG(CAST(field AS VARCHAR(max)), ',' + CHAR(10)) + ');' AS create_type
FROM (
SELECT TOP 5000 COLUMN_NAME + ' ' + DATA_TYPE
+ IIF(CHARACTER_MAXIMUM_LENGTH IS NULL, '', CONCAT('(', IIF(CHARACTER_MAXIMUM_LENGTH = -1, 'max', CONCAT(CHARACTER_MAXIMUM_LENGTH,'')), ')'))
+ IIF(DATA_TYPE = 'decimal', CONCAT('(', NUMERIC_PRECISION, ',', NUMERIC_SCALE, ')'), '')
AS field
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = '[table_name]'
ORDER BY ORDINAL_POSITION) AS T;
After updating the Table Type, the Data Export service started functioning properly once again! :)
When I tried to execute my stored procedure I had the same problem because the size of the column that I need to add some data is shorter than the data I want to add.
You can increase the size of the column data type or reduce the length of your data.
A 2016/2017 update will show you the bad value and column.
A new trace flag will swap the old error for a new 2628 error and will print out the column and offending value. Traceflag 460 is available in the latest cumulative update for 2016 and 2017:
https://support.microsoft.com/en-sg/help/4468101/optional-replacement-for-string-or-binary-data-would-be-truncated
Just make sure that after you've installed the CU that you enable the trace flag, either globally/permanently on the server:
...or with DBCC TRACEON:
https://learn.microsoft.com/en-us/sql/t-sql/database-console-commands/dbcc-traceon-trace-flags-transact-sql?view=sql-server-ver15
Another situation, in which this error may occur is in
SQL Server Management Studio. If you have "text" or "ntext" fields in your table,
no matter what kind of field you are updating (for example bit or integer).
Seems that the Studio does not load entire "ntext" fields and also updates ALL fields instead of the modified one.
To solve the problem, exclude "text" or "ntext" fields from the query in Management Studio
This Error Comes only When any of your field length is greater than the field length specified in sql server database table structure.
To overcome this issue you have to reduce the length of the field Value .
Or to increase the length of database table field .
If someone is encountering this error in a C# application, I have created a simple way of finding offending fields by:
Getting the column width of all the columns of a table where we're trying to make this insert/ update. (I'm getting this info directly from the database.)
Comparing the column widths to the width of the values we're trying to insert/ update.
Assumptions/ Limitations:
The column names of the table in the database match with the C# entity fields. For eg: If you have a column like this in database:
You need to have your Entity with the same column name:
public class SomeTable
{
// Other fields
public string SourceData { get; set; }
}
You're inserting/ updating 1 entity at a time. It'll be clearer in the demo code below. (If you're doing bulk inserts/ updates, you might want to either modify it or use some other solution.)
Step 1:
Get the column width of all the columns directly from the database:
// For this, I took help from Microsoft docs website:
// https://learn.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqlconnection.getschema?view=netframework-4.7.2#System_Data_SqlClient_SqlConnection_GetSchema_System_String_System_String___
private static Dictionary<string, int> GetColumnSizesOfTableFromDatabase(string tableName, string connectionString)
{
var columnSizes = new Dictionary<string, int>();
using (var connection = new SqlConnection(connectionString))
{
// Connect to the database then retrieve the schema information.
connection.Open();
// You can specify the Catalog, Schema, Table Name, Column Name to get the specified column(s).
// You can use four restrictions for Column, so you should create a 4 members array.
String[] columnRestrictions = new String[4];
// For the array, 0-member represents Catalog; 1-member represents Schema;
// 2-member represents Table Name; 3-member represents Column Name.
// Now we specify the Table_Name and Column_Name of the columns what we want to get schema information.
columnRestrictions[2] = tableName;
DataTable allColumnsSchemaTable = connection.GetSchema("Columns", columnRestrictions);
foreach (DataRow row in allColumnsSchemaTable.Rows)
{
var columnName = row.Field<string>("COLUMN_NAME");
//var dataType = row.Field<string>("DATA_TYPE");
var characterMaxLength = row.Field<int?>("CHARACTER_MAXIMUM_LENGTH");
// I'm only capturing columns whose Datatype is "varchar" or "char", i.e. their CHARACTER_MAXIMUM_LENGTH won't be null.
if(characterMaxLength != null)
{
columnSizes.Add(columnName, characterMaxLength.Value);
}
}
connection.Close();
}
return columnSizes;
}
Step 2:
Compare the column widths with the width of the values we're trying to insert/ update:
public static Dictionary<string, string> FindLongBinaryOrStringFields<T>(T entity, string connectionString)
{
var tableName = typeof(T).Name;
Dictionary<string, string> longFields = new Dictionary<string, string>();
var objectProperties = GetProperties(entity);
//var fieldNames = objectProperties.Select(p => p.Name).ToList();
var actualDatabaseColumnSizes = GetColumnSizesOfTableFromDatabase(tableName, connectionString);
foreach (var dbColumn in actualDatabaseColumnSizes)
{
var maxLengthOfThisColumn = dbColumn.Value;
var currentValueOfThisField = objectProperties.Where(f => f.Name == dbColumn.Key).First()?.GetValue(entity, null)?.ToString();
if (!string.IsNullOrEmpty(currentValueOfThisField) && currentValueOfThisField.Length > maxLengthOfThisColumn)
{
longFields.Add(dbColumn.Key, $"'{dbColumn.Key}' column cannot take the value of '{currentValueOfThisField}' because the max length it can take is {maxLengthOfThisColumn}.");
}
}
return longFields;
}
public static List<PropertyInfo> GetProperties<T>(T entity)
{
//The DeclaredOnly flag makes sure you only get properties of the object, not from the classes it derives from.
var properties = entity.GetType()
.GetProperties(System.Reflection.BindingFlags.Public
| System.Reflection.BindingFlags.Instance
| System.Reflection.BindingFlags.DeclaredOnly)
.ToList();
return properties;
}
Demo:
Let's say we're trying to insert someTableEntity of SomeTable class that is modeled in our app like so:
public class SomeTable
{
[Key]
public long TicketID { get; set; }
public string SourceData { get; set; }
}
And it's inside our SomeDbContext like so:
public class SomeDbContext : DbContext
{
public DbSet<SomeTable> SomeTables { get; set; }
}
This table in Db has SourceData field as varchar(16) like so:
Now we'll try to insert value that is longer than 16 characters into this field and capture this information:
public void SaveSomeTableEntity()
{
var connectionString = "server=SERVER_NAME;database=DB_NAME;User ID=SOME_ID;Password=SOME_PASSWORD;Connection Timeout=200";
using (var context = new SomeDbContext(connectionString))
{
var someTableEntity = new SomeTable()
{
SourceData = "Blah-Blah-Blah-Blah-Blah-Blah"
};
context.SomeTables.Add(someTableEntity);
try
{
context.SaveChanges();
}
catch (Exception ex)
{
if (ex.GetBaseException().Message == "String or binary data would be truncated.\r\nThe statement has been terminated.")
{
var badFieldsReport = "";
List<string> badFields = new List<string>();
// YOU GOT YOUR FIELDS RIGHT HERE:
var longFields = FindLongBinaryOrStringFields(someTableEntity, connectionString);
foreach (var longField in longFields)
{
badFields.Add(longField.Key);
badFieldsReport += longField.Value + "\n";
}
}
else
throw;
}
}
}
The badFieldsReport will have this value:
'SourceData' column cannot take the value of
'Blah-Blah-Blah-Blah-Blah-Blah' because the max length it can take is
16.
Kevin Pope's comment under the accepted answer was what I needed.
The problem, in my case, was that I had triggers defined on my table that would insert update/insert transactions into an audit table, but the audit table had a data type mismatch where a column with VARCHAR(MAX) in the original table was stored as VARCHAR(1) in the audit table, so my triggers were failing when I would insert anything greater than VARCHAR(1) in the original table column and I would get this error message.
I used a different tactic, fields that are allocated 8K in some places. Here only about 50/100 are used.
declare #NVPN_list as table
nvpn varchar(50)
,nvpn_revision varchar(5)
,nvpn_iteration INT
,mpn_lifecycle varchar(30)
,mfr varchar(100)
,mpn varchar(50)
,mpn_revision varchar(5)
,mpn_iteration INT
-- ...
) INSERT INTO #NVPN_LIST
SELECT left(nvpn ,50) as nvpn
,left(nvpn_revision ,10) as nvpn_revision
,nvpn_iteration
,left(mpn_lifecycle ,30)
,left(mfr ,100)
,left(mpn ,50)
,left(mpn_revision ,5)
,mpn_iteration
,left(mfr_order_num ,50)
FROM [DASHBOARD].[dbo].[mpnAttributes] (NOLOCK) mpna
I wanted speed, since I have 1M total records, and load 28K of them.
This error may be due to less field size than your entered data.
For e.g. if you have data type nvarchar(7) and if your value is 'aaaaddddf' then error is shown as:
string or binary data would be truncated
You simply can't beat SQL Server on this.
You can insert into a new table like this:
select foo, bar
into tmp_new_table_to_dispose_later
from my_table
and compare the table definition with the real table you want to insert the data into.
Sometime it's helpful sometimes it's not.
If you try inserting in the final/real table from that temporary table it may just work (due to data conversion working differently than SSMS for example).
Another alternative is to insert the data in chunks, instead of inserting everything immediately you insert with top 1000 and you repeat the process, till you find a chunk with an error. At least you have better visibility on what's not fitting into the table.