Schema Collections

The Schema collections return metadata for the Advanced SQL Engine objects. The notable metadata columns for the Number data type are:

Column Name	Description
COLUMN_TYPE or DATA_TYPE	Set to NUMBER.
NUMERIC_PRECISION	Set to 38.
FORMAT	Format assigned to the SQL Engine object.
PROVIDERDBTYPE	It is set to TdType.Number.
COLUMN_INFO	It is either set to FIXED or FLOAT. FIXED indicates that the NUMBER represents a fixed decimal. FLOAT indicates that the NUMBER represents a floating decimal.

Schema Table

The TdDataReader.GetSchemaTable returns result set metadata. The notable metadata columns for the Number data type are:

If the Number is a floating point decimal this column will be set null (DBNull.Value).

Column Name	Description
NumericPrecision	If the Number is a fixed point decimal the precision can range from 1 to 38 corresponding to the object (Column, Stored Procedure parameter ...) declaration. For a Number that is a floating point decimal the precision will be 38. This is the maximum number of digits supported in the mantissa.
NumericScale	For a Number that is a fixed point decimal the scale can range from 0 to 38 and corresponds to the object (Column, Stored Procedure parameter ...) declaration. It is equal to or less than the NumericPrecision.
DataType	System.Type object for the System.Double type.
ProviderType	Set to TdType.Number.
Format	Format assigned to the SQL Engine object.
ProviderSpecificDataType	System.Type object for the TdNumber structure.

Configuring Parameters

If the TdParameter.TdType property is set to TdType.Number the TdParameter.Precision and TdParameter.Scale properties do not need to be set. This holds whether the column/parameter is defined as a floating or fixed decimal.

The number will be rounded if the TdParameter.TdType property is defined as a TdType.Double. The reason for this is that TdNumber can support a mantissa of up to 38 digits. System.Double can only support a mantissa that is up to 15 digits.

C#	Copy Code
TdParameter quantity = new TdParameter(); quantity.TdType = TdType.Number; quantity.Value = TdNumber.Parse("435924.9999e-15");

The number that is to be inserted will be rounded at the 15 position --.000000000435925.

Note
The values for the TdParameter.Precision and TdParameter.Scale are ignored when the TdParameter.TdType property is set to TdType.Number.

The following example shows how to configure a TdNumber parameter using DbType type declaration and a BCL value.

C#	Copy Code
TdParameter quantity = new TdParameter(); quantity.DbType = DbType.Double; quantity.Value = 1000.23e10;

The following example shows how to configure a Number parameter using TdType type declaration and a Provider Specific value.

C#	Copy Code
TdParameter quantity = new TdParameter(); quantity.TdType = TdType.Number; quantity.ProviderSpecificValue = TdNumber.Parse("1.23456789076543210239458601992884799e36");

Retrieving Number Data

The following methods and properties return the column or parameter value as a System.Double structure.

The following Provider Specific Value methods and property return the column or parameter value as a TdNumber structure.

C#	Copy Code
using (TdConnection cn = new TdConnection("data source=DS1;UserId=Joe;Password=XY;")) { cn.Open(); TdCommand cmd = cn.CreateCommand(); // Price is defined as NUMBER(25, 2) cmd.CommandText = "SELECT Id, Price from Order where Quantity > ?"; cmd.Parameters.Add("quantity", TdType.Decimal); cmd.Parameters["quantity"].Value = 12561M; using (TdDataReader reader = cmd.ExecuteReader()) { if (reader.HasRows) { while (reader.Read()) { Console.WriteLine("[System.Double] Price = {0}", reader.GetDouble(1).ToString()); Console.WriteLine("[TdNumber] Price = {0}", reader.GetTdNumber(1).ToString()); } } } } /* Output: [System.Double] Price = 1.23456789012378e12; [TdNumber] Price = 1.23456789012378e12; */

Copy Code

using (TdConnection cn = new TdConnection("data source=DS1;UserId=Joe;Password=XY;"))
{
    cn.Open();

    TdCommand cmd = cn.CreateCommand();

    // Price is defined as NUMBER(25, 2)     cmd.CommandText = "SELECT Id, Price from Order where Quantity > ?";
    cmd.Parameters.Add("quantity", TdType.Decimal);
    cmd.Parameters["quantity"].Value = 12561M;

    using (TdDataReader reader = cmd.ExecuteReader())
    {
        if (reader.HasRows)
        {
            while (reader.Read())
            {
                Console.WriteLine("[System.Double] Price = {0}", reader.GetDouble(1).ToString());
                Console.WriteLine("[TdNumber] Price = {0}", reader.GetTdNumber(1).ToString());

            }
        }
    }
}

/* Output:
    [System.Double] Price = 1.23456789012378e12;
    [TdNumber] Price = 1.23456789012378e12;
*/

Schema Collections

Schema Table

Configuring Parameters

Retrieving Number Data

See Also