Get the generated SQL statement from a SqlCommand object?
You can't, because it does not generate any SQL.
The parameterized query (the one in CommandText) is sent to the SQL Server as the equivalent of a prepared statement. When you execute the command, the parameters and the query text are treated separately. At no point in time a complete SQL string is generated.
You can use SQL Profiler to take a look behind the scenes.
I needed a similar command to string transformer to allow for more verbose logging, so I wrote this one. It will produce the text needed to re-execute the command in a new session including output parameters and structured parameters. It is lightly tested, but caveat emptor.
Example:
SqlCommand cmd = new SqlCommand("GetEntity", con);
cmd.Parameters.AddWithValue("@foobar", 1);
cmd.Parameters.Add(new SqlParameter(){
ParameterName = "@outParam",
Direction = ParameterDirection.Output,
SqlDbType = System.Data.SqlDbType.Int
});
cmd.Parameters.Add(new SqlParameter(){
Direction = ParameterDirection.ReturnValue
});
cmd.CommandType = CommandType.StoredProcedure;
Will produce:
-- BEGIN COMMAND
DECLARE @foobar INT = 1;
DECLARE @outParam INT = NULL;
DECLARE @returnValue INT;
-- END PARAMS
EXEC @returnValue = GetEntity @foobar = @foobar, @outParam = @outParam OUTPUT
-- RESULTS
SELECT 1 as Executed, @returnValue as ReturnValue, @outParam as [@outParam];
-- END COMMAND
Implementation:
public class SqlCommandDumper
{
public static string GetCommandText(SqlCommand sqc)
{
StringBuilder sbCommandText = new StringBuilder();
sbCommandText.AppendLine("-- BEGIN COMMAND");
// params
for (int i = 0; i < sqc.Parameters.Count; i++)
logParameterToSqlBatch(sqc.Parameters[i], sbCommandText);
sbCommandText.AppendLine("-- END PARAMS");
// command
if (sqc.CommandType == CommandType.StoredProcedure)
{
sbCommandText.Append("EXEC ");
bool hasReturnValue = false;
for (int i = 0; i < sqc.Parameters.Count; i++)
{
if (sqc.Parameters[i].Direction == ParameterDirection.ReturnValue)
hasReturnValue = true;
}
if (hasReturnValue)
{
sbCommandText.Append("@returnValue = ");
}
sbCommandText.Append(sqc.CommandText);
bool hasPrev = false;
for (int i = 0; i < sqc.Parameters.Count; i++)
{
var cParam = sqc.Parameters[i];
if (cParam.Direction != ParameterDirection.ReturnValue)
{
if (hasPrev)
sbCommandText.Append(",");
sbCommandText.Append(" ");
sbCommandText.Append(cParam.ParameterName);
sbCommandText.Append(" = ");
sbCommandText.Append(cParam.ParameterName);
if (cParam.Direction.HasFlag(ParameterDirection.Output))
sbCommandText.Append(" OUTPUT");
hasPrev = true;
}
}
}
else
{
sbCommandText.AppendLine(sqc.CommandText);
}
sbCommandText.AppendLine("-- RESULTS");
sbCommandText.Append("SELECT 1 as Executed");
for (int i = 0; i < sqc.Parameters.Count; i++)
{
var cParam = sqc.Parameters[i];
if (cParam.Direction == ParameterDirection.ReturnValue)
{
sbCommandText.Append(", @returnValue as ReturnValue");
}
else if (cParam.Direction.HasFlag(ParameterDirection.Output))
{
sbCommandText.Append(", ");
sbCommandText.Append(cParam.ParameterName);
sbCommandText.Append(" as [");
sbCommandText.Append(cParam.ParameterName);
sbCommandText.Append(']');
}
}
sbCommandText.AppendLine(";");
sbCommandText.AppendLine("-- END COMMAND");
return sbCommandText.ToString();
}
private static void logParameterToSqlBatch(SqlParameter param, StringBuilder sbCommandText)
{
sbCommandText.Append("DECLARE ");
if (param.Direction == ParameterDirection.ReturnValue)
{
sbCommandText.AppendLine("@returnValue INT;");
}
else
{
sbCommandText.Append(param.ParameterName);
sbCommandText.Append(' ');
if (param.SqlDbType != SqlDbType.Structured)
{
logParameterType(param, sbCommandText);
sbCommandText.Append(" = ");
logQuotedParameterValue(param.Value, sbCommandText);
sbCommandText.AppendLine(";");
}
else
{
logStructuredParameter(param, sbCommandText);
}
}
}
private static void logStructuredParameter(SqlParameter param, StringBuilder sbCommandText)
{
sbCommandText.AppendLine(" {List Type};");
var dataTable = (DataTable)param.Value;
for (int rowNo = 0; rowNo < dataTable.Rows.Count; rowNo++)
{
sbCommandText.Append("INSERT INTO ");
sbCommandText.Append(param.ParameterName);
sbCommandText.Append(" VALUES (");
bool hasPrev = false;
for (int colNo = 0; colNo < dataTable.Columns.Count; colNo++)
{
if (hasPrev)
{
sbCommandText.Append(", ");
}
logQuotedParameterValue(dataTable.Rows[rowNo].ItemArray[colNo], sbCommandText);
hasPrev = true;
}
sbCommandText.AppendLine(");");
}
}
const string DATETIME_FORMAT_ROUNDTRIP = "o";
private static void logQuotedParameterValue(object value, StringBuilder sbCommandText)
{
try
{
if (value == null)
{
sbCommandText.Append("NULL");
}
else
{
value = unboxNullable(value);
if (value is string
|| value is char
|| value is char[]
|| value is System.Xml.Linq.XElement
|| value is System.Xml.Linq.XDocument)
{
sbCommandText.Append("N'");
sbCommandText.Append(value.ToString().Replace("'", "''"));
sbCommandText.Append('\'');
}
else if (value is bool)
{
// True -> 1, False -> 0
sbCommandText.Append(Convert.ToInt32(value));
}
else if (value is sbyte
|| value is byte
|| value is short
|| value is ushort
|| value is int
|| value is uint
|| value is long
|| value is ulong
|| value is float
|| value is double
|| value is decimal)
{
sbCommandText.Append(value.ToString());
}
else if (value is DateTime)
{
// SQL Server only supports ISO8601 with 3 digit precision on datetime,
// datetime2 (>= SQL Server 2008) parses the .net format, and will
// implicitly cast down to datetime.
// Alternatively, use the format string "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffK"
// to match SQL server parsing
sbCommandText.Append("CAST('");
sbCommandText.Append(((DateTime)value).ToString(DATETIME_FORMAT_ROUNDTRIP));
sbCommandText.Append("' as datetime2)");
}
else if (value is DateTimeOffset)
{
sbCommandText.Append('\'');
sbCommandText.Append(((DateTimeOffset)value).ToString(DATETIME_FORMAT_ROUNDTRIP));
sbCommandText.Append('\'');
}
else if (value is Guid)
{
sbCommandText.Append('\'');
sbCommandText.Append(((Guid)value).ToString());
sbCommandText.Append('\'');
}
else if (value is byte[])
{
var data = (byte[])value;
if (data.Length == 0)
{
sbCommandText.Append("NULL");
}
else
{
sbCommandText.Append("0x");
for (int i = 0; i < data.Length; i++)
{
sbCommandText.Append(data[i].ToString("x"));
}
}
}
else
{
sbCommandText.Append("/* UNKNOWN DATATYPE: ");
sbCommandText.Append(value.GetType().ToString());
sbCommandText.Append(" *" + "/ N'");
sbCommandText.Append(value.ToString());
sbCommandText.Append('\'');
}
}
}
catch (Exception ex)
{
sbCommandText.AppendLine("/* Exception occurred while converting parameter: ");
sbCommandText.AppendLine(ex.ToString());
sbCommandText.AppendLine("*/");
}
}
private static object unboxNullable(object value)
{
var typeOriginal = value.GetType();
if (typeOriginal.IsGenericType
&& typeOriginal.GetGenericTypeDefinition() == typeof(Nullable<>))
{
// generic value, unboxing needed
return typeOriginal.InvokeMember("GetValueOrDefault",
System.Reflection.BindingFlags.Public |
System.Reflection.BindingFlags.Instance |
System.Reflection.BindingFlags.InvokeMethod,
null, value, null);
}
else
{
return value;
}
}
private static void logParameterType(SqlParameter param, StringBuilder sbCommandText)
{
switch (param.SqlDbType)
{
// variable length
case SqlDbType.Char:
case SqlDbType.NChar:
case SqlDbType.Binary:
{
sbCommandText.Append(param.SqlDbType.ToString().ToUpper());
sbCommandText.Append('(');
sbCommandText.Append(param.Size);
sbCommandText.Append(')');
}
break;
case SqlDbType.VarBinary:
case SqlDbType.Image:
{
sbCommandText.Append("VARBINARY");
sbCommandText.Append("(MAX /* Specified as ");
sbCommandText.Append(param.Size);
sbCommandText.Append(" */)");
}
break;
case SqlDbType.VarChar:
case SqlDbType.Text:
{
sbCommandText.Append("VARCHAR");
sbCommandText.Append("(MAX /* Specified as ");
sbCommandText.Append(param.Size);
sbCommandText.Append(" */)");
}
break;
case SqlDbType.NVarChar:
case SqlDbType.NText:
{
sbCommandText.Append("NVARCHAR");
sbCommandText.Append("(MAX /* Specified as ");
sbCommandText.Append(param.Size);
sbCommandText.Append(" */)");
}
break;
// fixed length
case SqlDbType.Bit:
case SqlDbType.TinyInt:
case SqlDbType.SmallInt:
case SqlDbType.Int:
case SqlDbType.BigInt:
case SqlDbType.SmallMoney:
case SqlDbType.Money:
case SqlDbType.Decimal:
case SqlDbType.Real:
case SqlDbType.Float:
case SqlDbType.Date:
case SqlDbType.DateTime:
case SqlDbType.DateTime2:
case SqlDbType.DateTimeOffset:
case SqlDbType.UniqueIdentifier:
{
sbCommandText.Append(param.SqlDbType.ToString().ToUpper());
}
break;
// Unknown
case SqlDbType.Timestamp:
default:
{
sbCommandText.Append("/* UNKNOWN DATATYPE: ");
sbCommandText.Append(param.SqlDbType.ToString().ToUpper());
sbCommandText.Append(" *" + "/ ");
sbCommandText.Append(param.SqlDbType.ToString().ToUpper());
}
break;
}
}
}
Whilst not perfect, here's something I knocked up for TSQL - could be easily tweaked for other flavors... If nothing else it will give you a start point for your own improvements :)
This does an OK job on data types and output parameters etc similar to using "execute stored procedure" in SSMS. We mostly used SPs so the "text" command doesn't account for parameters etc
public static String ParameterValueForSQL(this SqlParameter sp)
{
String retval = "";
switch (sp.SqlDbType)
{
case SqlDbType.Char:
case SqlDbType.NChar:
case SqlDbType.NText:
case SqlDbType.NVarChar:
case SqlDbType.Text:
case SqlDbType.Time:
case SqlDbType.VarChar:
case SqlDbType.Xml:
case SqlDbType.Date:
case SqlDbType.DateTime:
case SqlDbType.DateTime2:
case SqlDbType.DateTimeOffset:
retval = "'" + sp.Value.ToString().Replace("'", "''") + "'";
break;
case SqlDbType.Bit:
retval = (sp.Value.ToBooleanOrDefault(false)) ? "1" : "0";
break;
default:
retval = sp.Value.ToString().Replace("'", "''");
break;
}
return retval;
}
public static String CommandAsSql(this SqlCommand sc)
{
StringBuilder sql = new StringBuilder();
Boolean FirstParam = true;
sql.AppendLine("use " + sc.Connection.Database + ";");
switch (sc.CommandType)
{
case CommandType.StoredProcedure:
sql.AppendLine("declare @return_value int;");
foreach (SqlParameter sp in sc.Parameters)
{
if ((sp.Direction == ParameterDirection.InputOutput) || (sp.Direction == ParameterDirection.Output))
{
sql.Append("declare " + sp.ParameterName + "\t" + sp.SqlDbType.ToString() + "\t= ");
sql.AppendLine(((sp.Direction == ParameterDirection.Output) ? "null" : sp.ParameterValueForSQL()) + ";");
}
}
sql.AppendLine("exec [" + sc.CommandText + "]");
foreach (SqlParameter sp in sc.Parameters)
{
if (sp.Direction != ParameterDirection.ReturnValue)
{
sql.Append((FirstParam) ? "\t" : "\t, ");
if (FirstParam) FirstParam = false;
if (sp.Direction == ParameterDirection.Input)
sql.AppendLine(sp.ParameterName + " = " + sp.ParameterValueForSQL());
else
sql.AppendLine(sp.ParameterName + " = " + sp.ParameterName + " output");
}
}
sql.AppendLine(";");
sql.AppendLine("select 'Return Value' = convert(varchar, @return_value);");
foreach (SqlParameter sp in sc.Parameters)
{
if ((sp.Direction == ParameterDirection.InputOutput) || (sp.Direction == ParameterDirection.Output))
{
sql.AppendLine("select '" + sp.ParameterName + "' = convert(varchar, " + sp.ParameterName + ");");
}
}
break;
case CommandType.Text:
sql.AppendLine(sc.CommandText);
break;
}
return sql.ToString();
}
this generates output along these lines...
use dbMyDatabase;
declare @return_value int;
declare @OutTotalRows BigInt = null;
exec [spMyStoredProc]
@InEmployeeID = 1000686
, @InPageSize = 20
, @InPage = 1
, @OutTotalRows = @OutTotalRows output
;
select 'Return Value' = convert(varchar, @return_value);
select '@OutTotalRows' = convert(varchar, @OutTotalRows);
For logging purposes, I'm afraid there's no nicer way of doing this but to construct the string yourself:
string query = cmd.CommandText;
foreach (SqlParameter p in cmd.Parameters)
{
query = query.Replace(p.ParameterName, p.Value.ToString());
}