Using AS400 date in SSRS Report

问题

Running a SELECT against the AS400 using the IBMDA400 OleDb provider appears to return dates as string values, SSRS just laughs at you when you try and apply a date format to the field. I've tried a simple CAST in the SELECT to no avail.

How can I get an actual DBTYPE_DBDATE struct back from the iSeries OleDb provider?

I should mention that the dates in question are all being returned by a UDF with a type of DATE. IBM appears to map DATE type into a DBTYPE_STR OleDb type.

回答1:

The field(s) in the table(s) are probably not defined as a date type. You will need to convert them using the DATE function as part of the query.

You can use the DSPFFD command, the Navigator, or query the SYSIBM.SQLCOLUMNS table to view the field definitions.

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UPDATE

After further testing with the IBMDA400 provider I found the Convert Date Time To Char property hidden away in the OLE DB Technical Reference installed as part of the Programmer's Toolkit with Access. The default value is TRUE. Set Convert Date Time To Char=FALSE in the connection string or properties to disable this 'feature'.

Here's a quick VBA test:

Set cn = CreateObject("ADODB.Connection")
cn.Open "Provider=IBMDA400;Data Source=...;User ID=...;Password=...;Convert Date Time To Char=FALSE"
Set rs = cn.Execute("SELECT DATE(NOW()) FROM SYSIBM.SYSDUMMY1")
MsgBox "Returned ADO type: " & rs.Fields(0).Type

See MSDN: DataTypeEnum for the possible ADO data types. adDBDate is 133.

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IBM i Access for Windows OLE DB Technical Reference

IBM i OLE DB provider functions > Special Properties

Convert Date Time To Char

Specifies conversion of DB2 for IBM i Date, Time, and Timestamp data types to corresponding PC data types and vice versa.

Settings and Return Values

Sets or returns one of the following string values. The default value is "TRUE".

"TRUE"

DB2 for IBM i Date, Time, and Timestamp data types are treated as character strings. When reading IBM i data, these values are converted to character strings. When writing data to the system, character strings are expected as input for these values. The supported character string format for the Date data type is ISO format: yyyy-mm-dd. The supported character string format for the Time data type is the earlier version of the ISO format: hh.mm.ss. The supported character string format for the Timestamp data type is: yyyy-mm-dd-hh.mm.ss.nnnnnn.

"FALSE"

DB2 for IBM i Date, Time, and Timestamp data types will be converted to PC Date, Time, and Timestamp data types. Care should be taken when using this value in an environment that only supports the Variant Date data type (such as Visual Basic). You may encounter unexpected errors due to truncation or overflow caused by the limitations of the Variant Date data type.

Following are additional considerations when Convert Date Time To Char is FALSE.

• The variant Date data type, which is actually a timestamp, does not support micro-seconds - the precision of the DB2 for IBM i timestamp. The OLE DB provider will truncate the fractional timestamp without reporting an error. For example, 1990-03-02-08.30.00.100517 will become 1990-03-02-08.30.00.000000. All updated or inserted timestamp values will have 0 micro-seconds.
• Leap second overflow error. The OLE DB timestamp allows up to two leap seconds (a value of 60 or 61). DB2 for IBM i supports a maximum value of 59. An overflow error is returned if leap seconds are set.
• The variant Date data type does not support the data limits of an ISO date or timestamp. The value "0001-01-01", used as a default date in many databases, including DB2 for IBM i, will cause an overflow.
• DB2 for IBM i supports a time value of 24:00:00 for certain older formats of the TIME data type. The OLE DB provider will convert values of 24:00:00 to 00:00:00 without any error message or warning.
• Typically for VB variant, a date value of 1899-12-30 (which is a 0 date) is used to imply a Time only variant date. A time of Midnight (00:00:00) is used to imply a Date only variant date.

Remarks

This custom property is available on the ADO connection object. The property is read/write when the connection is closed and read-only when the connection is open.

Delphi example

<connection>.Provider := 'IBMDA400';
<connection>.Properties('Convert Date Time To Char') := "TRUE";

OR

<connection>.Open('Provider=IBMDA400;Data Source=SystemA;Convert Date Time To Char =TRUE', 'Userid', 'Password');

PowerBuilder example

<connection>.Provider = "IBMDA400"
SetProperty(<connection>), "Convert Date Time To Char", "TRUE")

OR

<connection>.Open("Provider=IBMDA400;Data Source=SystemA;Convert Date Time To Char=TRUE", "Userid", "Password")

Visual Basic example

<connection>.Provider = "IBMDA400"
<connection>.Properties("Convert Date Time To Char") = "TRUE"

AND/OR

<connection>.Open "Provider=IBMDA400;Data Source=SystemA;Convert Date Time To Char=TRUE", "Userid", "Password")

回答2:

It appears the correct answer is, you can't. No way, no how, does the IBMDA400 provider map any type into a DBTYPE_DBDATE.

What you can do is use the DateValue() SSRS function to convert the returned DBTYPE_STR value to a date/time serial. From there the format functions will work on it.

I didn't have a problem, here in North America, with the DateValue() function directly interpreting the returned DBTYPE_STR value, however, this could be an issue in other locales due to date format differences.

来源：https://stackoverflow.com/questions/17951804/using-as400-date-in-ssrs-report