the table below shows the ado data type mapping between access, sql server, and oracle:

datatype enumvalueaccesssqlserveroracleadbigint20 bigint (sql server 2000 +) adbinary128 binary
timestampraw *adboolean11yesnobit adchar129 charcharadcurrency6currencymoney
smallmoney addate7datedatetime addbtimestamp135datetime (access 97 (odbc))datetime
smalldatetimedateaddecimal14  decimal *addouble5doublefloatfloatadguid72replicationid (access 97 (oledb)), (access 2000 (oledb))uniqueidentifier (sql server 7.0 +) adidispatch9   adinteger3autonumber
integer
longidentity (sql server 6.5)
int
 int *adlongvarbinary205oleobjectimagelong raw *
blob (oracle 8.1.x)adlongvarchar201memo (access 97)
hyperlink (access 97)textlong *
clob (oracle 8.1.x)adlongvarwchar203memo (access 2000 (oledb))
hyperlink (access 2000 (oledb))ntext (sql server 7.0 +)nclob (oracle 8.1.x)adnumeric131decimal (access 2000 (oledb))decimal
numericdecimal
integer
number
smallintadsingle4singlereal adsmallint2integersmallint adunsignedtinyint17bytetinyint advarbinary204replicationid (access 97)varbinary advarchar200text (access 97)varcharvarcharadvariant12 sql_variant (sql server 2000 +)varchar2advarwchar202text (access 2000 (oledb))nvarchar (sql server 7.0 +)nvarchar2adwchar130 nchar (sql server 7.0 +) 

* in oracle 8.0.x - decimal and int are equal to number and number(10).