Connectivity Guide > Understanding .NET Data Provider Connectivity > Data Types Mapping
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Data Types Mapping
The .NET Data Provider defines its own enumeration of supported data types in addition to the standard System.Data.DbType enumeration.
The following table shows the mapping of the .NET Data Provider's data types to its .NET data type counterparts. For information on the typed accessors that a .NET application uses for an Ingres native database type to be obtained as a .NET type, see IngresDataReader Class.
IngresType
Ingres
Data Type
Description
.NET Data Type
Binary
byte
Fixed length stream of binary data
Byte[ ]
Boolean
boolean
Boolean values of true and false
Boolean
Char
char
Fixed length stream of character data
String
Date
ansidate
Date data
DateTime
Time
time
Time data
DateTime
DateTime
timestamp
Date and time data
DateTime
IngresDate
ingresdate
Ingres format date
DateTime
IntervalYearToMonth
interval year to month
Interval year to month
String
IntervalDayToSecond
interval day to second
Interval day to second
TimeSpan
Decimal
decimal
Exact numeric data
Decimal
Double
double precision (float8)
Approximate numeric data
Double
SmallInt
smallint
Signed 16-bit integer data
Int16
TinyInt
integer1
Signed 8-bit integer data
SByte
Int
integer
Signed 32-bit integer data
Int32
BigInt
bigint
Signed 64-bit integer data
Int64
LongVarBinary
long byte
Binary large object
Byte[ ]
LongVarChar
long varchar
Character large object
String
LongNVarChar
long nvarchar
Unicode large object
String
NChar
nchar
Fixed length stream of Unicode data
String
NVarChar
nvarchar
Variable length stream of Unicode data
String
Real
real (float4)
Approximate numeric data
Single
VarBinary
byte varying
Variable length stream of binary data
Byte[ ]
VarChar
varchar
Variable length stream of character data
String
Notes:
• DateTime literals within SQL CommandText must be specified in the form of {d 'yyyy-mm-dd'} for dates and {ts 'yyyy-mm-dd hh-mm-ss'} for timestamps. However, it is preferable to pass .NET DateTime parameters rather than literals for these values.
• For Ingres servers, DateTime parameters are converted to UTC values before being sent to the Ingres servers. DateTime values retrieved from Ingres servers are converted from UTC values to Local values. For non-Ingres servers, DateTime values are passed between the data provider and servers unchanged.
• IngresType.DateTime parameter data is sent by the data provider depending on the level of support of the ANSI datetime data types. You can override the default behavior by specifying the IngresType.IngresDate data type for the parameter data rather than IngresType.DateTime. IngresType.IngresDate parameter data type forces the data provider to send the datetime parameter data as INGRESDATE type and value. For more information, see SendIngresDates Connection Keyword.
DbType Mapping
.NET’s System.Data.DbType for a parameter is mapped to the IngresType data type as follows:
DbType
IngresType
AnsiString
VarChar
AnsiStringFixedLength
Char
Binary
VarBinary
Boolean
Boolean
Byte
Binary, if supported by the database; otherwise, Char
Currency
Decimal
Date
DateTime
DateTime
DateTime
Decimal
Decimal
Double
Double
Guid
Not supported
Int16
SmallInt
Int32
Int
Int64
Decimal
Object
Not supported
SByte
TinyInt, if supported by the database; otherwise, SmallInt
Single
Real
String
NVarChar , if supported by the database; otherwise, VarChar
StringFixedLength
NChar, if supported by the database; otherwise, Char
Time
DateTime
UInt16
Int
UInt32
Decimal
UInt64
Decimal
VarNumeric
Decimal
Coercion of Unicode Strings
.NET strings are Unicode based. If the application is sending a Unicode string as a parameter to a database field that is ASCII char or varchar, the application can direct the data provider to coerce the Unicode string to an ASCII string on the client side by setting the IngresParameter’s DbType property to DbType.AnsiString or the IngresType property to IngresType.VarChar.
The following is an example of coercing a Unicode string:
IngresCommand cmd = new IngresCommand(
    "select name from personnel where ssn = ?",
    conn);

IngresParameter parm =
    new IngresParameter("SSN", IngresType.VarChar);
parm.Value = strSSN;
cmd.Parameters.Add(parm);
Last modified date: 12/12/2024