Re: OleDbLiteral
From: Edward Diener (diener_no_spam_ok_at_ORsoftware.com)
Date: 12/29/04
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Date: Wed, 29 Dec 2004 09:02:51 -0500
"Paul Clement" <UseAdddressAtEndofMessage@swspectrum.com> wrote in message
news:aek3t09omc1e2ra32oe7g7gjsjo9vd48a7@4ax.com...
> On Tue, 28 Dec 2004 13:22:26 -0500, "Edward Diener"
> <diener_no_spam_ok@ORsoftware.com> wrote:
>
> ¤ > ¤ > ¤ > ¤ Does System.Data.OleDb.OleDbLiteral have a purpose or is it
> just
> ¤ > ¤ > there
> ¤ > ¤ > ¤ > to
> ¤ > ¤ > ¤ > ¤ look good, as if it is used by something when it is not, or
> will
> ¤ > be
> ¤ > ¤ > used
> ¤ > ¤ > ¤ > in
> ¤ > ¤ > ¤ > ¤ something in the future ?
> ¤ > ¤ > ¤ > ¤
> ¤ > ¤ > ¤ >
> ¤ > ¤ > ¤ > I guess it depends upon how much you work with OLEDB
> interfaces.
> ¤ > It's
> ¤ > ¤ > ¤ > simply a constant enumerator
> ¤ > ¤ > ¤ > that maps to a corresponding enumerator in OLEDB. Similar to
> ¤ > ¤ > ¤ > System.Data.OleDb.OleDbType.
> ¤ > ¤ > ¤ >
> ¤ > ¤ > ¤
> ¤ > ¤ > ¤ It does not appear that there is anything in ADO .NET which uses
> it
> ¤ > ¤ > since
> ¤ > ¤ > ¤ there are no db properties in ADO .NET. Is it meant to be used
> by
> ¤ > ¤ > calling
> ¤ > ¤ > ¤ ADO from ADO .NET code ? That would be a novel design idea.
> ¤ > ¤ > ¤
> ¤ > ¤ >
> ¤ > ¤ > I've not used it but it appears to be for interfacing with OLEDB,
> not
> ¤ > ADO.
> ¤ > ¤
> ¤ > ¤ How is one supposed to interface with OLEDB from within ADO .NET,
> even
> ¤ > ¤ considering one is using the System.Data.OleDb set of classes ? I do
> not
> ¤ > see
> ¤ > ¤ anything in those classes which allows one to access OLEDB ActiveX
> ¤ > objects
> ¤ > ¤ from the System.Data.OleDb classes of ADO .NET.
> ¤ > ¤
> ¤ >
> ¤ > I don't think that is what I'm saying. The System.Data.OleDb managed
> ¤ > provider
> ¤ > interfaces with OLEDB using several classes. If you're looking for the
> ¤ > specific
> ¤ > .NET mechanism I would have to say it's schema related, probably the
> ¤ > GetOleDbSchemaTable method.
> ¤
> ¤ Getting schema information gets information about a particular database
> but
> ¤ I do not see how this interfaces with OleDbLiteral nor do I see how
> schema
> ¤ information gets me the sort of RDBMS specific information to which
> ¤ OleDbLiteral refers.
> ¤
>
> They are literal values returned when you query the database schema using
> OleDbSchemaGuid.DbInfoLiterals:
>
> http://msdn.microsoft.com/library/en-us/cpref/html/frlrfsystemdataoledboledbschemaguidclassdbinfoliteralstopic.asp?frame=true
OK, I see where the literal values are returned as a table if one uses
'DataTable dt = conn.GetOleDbSchemaTable(OleDbSchemaGuid.DbInfoLiterals,new
object[x])' etc.. What the columns are in this returned table I do not know
but I can experiment to find out. This is a good way of getting some RDBMS
specific information. I guess OleDbLiteral can be used in the situation to
specify a restriction for a column value once I can figure out what columns
are being returned..
>
> The corresponding usage in ADO is OpenSchema with adSchemaDBInfoLiterals.
>
> ¤ I am not looking for information about database objects but rather about
> the
> ¤ RDBMS itself. This is what OleDbLiteral implies. If you can find any
> usage
> ¤ for OleDbLiteral in order to obtain information about the RDBMS, it
> would be
> ¤ appreciated, otherwise I will assume that it is in there just to look
> good.
> ¤
>
> If you're looking for specific information about the RDBMS you may want to
> specify what those are, and identify the methods that were used in ADO. I
> don't
> understand the distinction you're making between the RDBMS and it's
> objects.
If RDBMS specific information, rather than database specific information,
can be found out by querying schema tables using GetOleDbSchemaTable then I
am fine, and will experiment with that. The distinction I make is that
normally one thinks of a database as having specific information in its
tables, about which one can query using schema access, while an RDBMS may
have specific rules regarding its syntax, transaction support, connection
support etc. etc. which one does not think of as being specific to a
connection, database, and its tables. However if querying for schema
information can also returns information in table format regarding RDBMS
specific information rather than just a particular connection's database
specific information, I will investigate that.
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