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GetSchema DATA_TYPE

I am capable of retrieving an OleDbSchema correctly. My question is that I always get a return of a type integer for DATA_TYPE. Is there a place that indicates what DataType is represented by each integer? If it makes a difference this is an Access DB.
[258 byte] By [RLovelett] at [2008-1-2]
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# 1
I'm not sure if I made it clear what I'm trying to do here. I am trying to make sure that the Access database the user has selected is in-fact the correct type of database to perform the actions that my program can.

So I am setting up a class that can look for the tables/columns and compare them to what they should be. Here is one of my methods:

Code Snippet

private static DataTable GetColumnSchema(ref OleDbConnection connection, String table_name) {
DataTable SchemaTable = new DataTable();

if (connection.State == ConnectionState.Open) {

// Get all the columns currently in the table;
// see: http://support.microsoft.com/kb/309681
// how GetOleDBSchemaTable works.
SchemaTable = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Columns, new Object[] { null, null, table_name, null });

for (int i = 0; i < SchemaTable.Rows.Count; i++) { // Loop through all the rows
foreach (DataColumn col in SchemaTable.Columns) {// Loop through all the columns available
MessageBox.Show(col.ColumnName + "[" + col.Ordinal + "] => " + Convert.ToString(SchemaTable.Rows[i].ItemArray[col.Ordinal]) + " " + System.Type.GetTypeCode(System.Type.GetType("System.DateTime")).ToString());
}
}
}

return SchemaTable;

}


My problem is where I'm looping through everything I eventually hit a column name DATA_TYPE. This holds a integer value, I am trying to discover what this integer value represents. Thanks.
RLovelett at 2007-9-13 > top of Msdn Tech,.NET Development,.NET Framework Data Access and Storage...
# 2
Bascially, it corresponds to OleDbType enum. http://msdn2.microsoft.com/en-us/library/system.data.oledb.oledbtype.aspx
BillLin-MSFT at 2007-9-13 > top of Msdn Tech,.NET Development,.NET Framework Data Access and Storage...
# 3
Bill,

I see all the member names in a table. My problem is that I do not see where in the table it says for instance WChar = 130. I lot of people have referred me to these tables, I guess I'm just not understanding how I should read them. Really, apologize for being this obtuse I just really don't see the correlation.

Thanks!

RLovelett at 2007-9-13 > top of Msdn Tech,.NET Development,.NET Framework Data Access and Storage...
# 4

The numbers are defined in Metadata. You could cast it to (OleDbType). Anyway, I give you the full table:

using System;

namespace System.Data.OleDb {

// Summary:

// Specifies the data type of a field, a property, for use in an System.Data.OleDb.OleDbParameter.

public enum OleDbType {

// Summary:

// No value (DBTYPE_EMPTY).

Empty = 0,

//

// Summary:

// A 16-bit signed integer (DBTYPE_I2). This maps to System.Int16.

SmallInt = 2,

//

// Summary:

// A 32-bit signed integer (DBTYPE_I4). This maps to System.Int32.

Integer = 3,

//

// Summary:

// A floating-point number within the range of -3.40E +38 through 3.40E +38

// (DBTYPE_R4). This maps to System.Single.

Single = 4,

//

// Summary:

// A floating-point number within the range of -1.79E +308 through 1.79E +308

// (DBTYPE_R8). This maps to System.Double.

Double = 5,

//

// Summary:

// A currency value ranging from -2 63 (or -922,337,203,685,477.5808) to 2 63

// -1 (or +922,337,203,685,477.5807) with an accuracy to a ten-thousandth of

// a currency unit (DBTYPE_CY). This maps to System.Decimal.

Currency = 6,

//

// Summary:

// Date data, stored as a double (DBTYPE_DATE). The whole portion is the number

// of days since December 30, 1899, and the fractional portion is a fraction

// of a day. This maps to System.DateTime.

Date = 7,

//

// Summary:

// A null-terminated character string of Unicode characters (DBTYPE_BSTR). This

// maps to System.String.

BSTR = 8,

//

// Summary:

// A pointer to an IDispatch interface (DBTYPE_IDISPATCH). This maps to System.Object.

IDispatch = 9,

//

// Summary:

// A 32-bit error code (DBTYPE_ERROR). This maps to System.Exception.

Error = 10,

//

// Summary:

// A Boolean value (DBTYPE_BOOL). This maps to System.Boolean.

Boolean = 11,

//

// Summary:

// A special data type that can contain numeric, string, binary, or date data,

// and also the special values Empty and Null (DBTYPE_VARIANT). This type is

// assumed if no other is specified. This maps to System.Object.

Variant = 12,

//

// Summary:

// A pointer to an IUnknown interface (DBTYPE_UNKNOWN). This maps to System.Object.

IUnknown = 13,

//

// Summary:

// A fixed precision and scale numeric value between -10 38 -1 and 10 38 -1

// (DBTYPE_DECIMAL). This maps to System.Decimal.

Decimal = 14,

//

// Summary:

// A 8-bit signed integer (DBTYPE_I1). This maps to System.SByte.

TinyInt = 16,

//

// Summary:

// A 8-bit unsigned integer (DBTYPE_UI1). This maps to System.Byte.

UnsignedTinyInt = 17,

//

// Summary:

// A 16-bit unsigned integer (DBTYPE_UI2). This maps to System.UInt16.

UnsignedSmallInt = 18,

//

// Summary:

// A 32-bit unsigned integer (DBTYPE_UI4). This maps to System.UInt32.

UnsignedInt = 19,

BigInt = 20,

//

// Summary:

// A 64-bit unsigned integer (DBTYPE_UI8). This maps to System.UInt64.

UnsignedBigInt = 21,

//

// Summary:

// A 64-bit unsigned integer representing the number of 100-nanosecond intervals

// since January 1, 1601 (DBTYPE_FILETIME). This maps to System.DateTime.

Filetime = 64,

//

// Summary:

// A globally unique identifier (or GUID) (DBTYPE_GUID). This maps to System.Guid.

Guid = 72,

//

// Summary:

// A stream of binary data (DBTYPE_BYTES). This maps to an System.Array of type

// System.Byte.

Binary = 128,

//

// Summary:

// A character string (DBTYPE_STR). This maps to System.String.

Char = 129,

//

// Summary:

// A null-terminated stream of Unicode characters (DBTYPE_WSTR). This maps to

// System.String.

WChar = 130,

//

// Summary:

// An exact numeric value with a fixed precision and scale (DBTYPE_NUMERIC).

// This maps to System.Decimal.

Numeric = 131,

//

// Summary:

// Date data in the format yyyymmdd (DBTYPE_DBDATE). This maps to System.DateTime.

DBDate = 133,

//

// Summary:

// Time data in the format hhmmss (DBTYPE_DBTIME). This maps to System.TimeSpan.

DBTime = 134,

//

// Summary:

// Data and time data in the format yyyymmddhhmmss (DBTYPE_DBTIMESTAMP). This

// maps to System.DateTime.

DBTimeStamp = 135,

//

// Summary:

// An automation PROPVARIANT (DBTYPE_PROP_VARIANT). This maps to System.Object.

PropVariant = 138,

//

// Summary:

// A variable-length numeric value (System.Data.OleDb.OleDbParameter only).

// This maps to System.Decimal.

VarNumeric = 139,

//

// Summary:

// A variable-length stream of non-Unicode characters (System.Data.OleDb.OleDbParameter

// only). This maps to System.String.

VarChar = 200,

//

// Summary:

// A long string value (System.Data.OleDb.OleDbParameter only). This maps to

// System.String.

LongVarChar = 201,

//

// Summary:

// A variable-length, null-terminated stream of Unicode characters (System.Data.OleDb.OleDbParameter

// only). This maps to System.String.

VarWChar = 202,

//

// Summary:

// A long null-terminated Unicode string value (System.Data.OleDb.OleDbParameter

// only). This maps to System.String.

LongVarWChar = 203,

//

// Summary:

// A variable-length stream of binary data (System.Data.OleDb.OleDbParameter

// only). This maps to an System.Array of type System.Byte.

VarBinary = 204,

//

// Summary:

// A long binary value (System.Data.OleDb.OleDbParameter only). This maps to

// an System.Array of type System.Byte.

LongVarBinary = 205,

}

}
BillLin-MSFT at 2007-9-13 > top of Msdn Tech,.NET Development,.NET Framework Data Access and Storage...
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