How to get tables/views/columns in ODBC (& OleDb)

[David Thielen]

Hi;

Note, this is all with ADO.NET using the ODBC and OleDb drivers

We've been using DataTable schemaTable = conn.GetSchema("views");
which was working ok and now we are finding some drivers where under
both ODBC and OleDb it is now returning hundreds of system views -
while table still seems to be ok (for now).

So my question is, how do I get the following from ODBC and OleDb in a
way that will work on all databases. And if there is no way to do
that, how do I do it for Sql Server 2000, Sql Server 2005, and Access.

1) Enumerate all user tables in a database.
2) Enumerate all tables (user & system) in a database.
3) Enumerate all user views in a database.
4) Enumerate all views (user & system) in a database.

5) Enumerate all columns in a table or view.
6) For a column, get it's data type.

7) Enumerate all user stored procedures in a database
8) Enumerate all stored procedures (user & system) in a database.
9) For a stored procedure, get all parameters and their data type.

10) For all objects - get the description of it in the metadata.

From reading the specs for ODBC and OleDb it seems that everything
above (with the possible exception of item 9) should be doable in a
standard way that works for every implementation.

Help please.

thanks - dave

david@at-at-at@windward.dot.dot.net
Windward Reports -- http://www.WindwardReports.com
me -- http://dave.thielen.com

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[Jialiang Ge [MSFT]]

Hello Dave,

The collection of DB schema information VARIES in different providers and
drivers. The common schema collection that are supported by all the managed
providers is documented at:

Understanding the Common Schema Collections
http://msdn.microsoft.com/en-us/library/ms254501(VS.80).aspx

But this collection does not include your requested information like all
user tables in a DB. To get the detailed schema info, we would need to
first decide the DB (SQL Server/Oracle/Access, etc) and the provider
(OLEDB/ODBC/ Microsoft .NET Framework Data Provider). For each combination,
we have provider-specific schema collections:

Understanding the Provider-Specific Schema Collections
http://msdn.microsoft.com/en-us/library/ms254969(VS.80).aspx

Some of them provide restricted collection of info; some provide the
details that may meet our needs.

So back to your questions:

1. how do I get the following from ODBC and OleDb in a way that will work
on all databases
This is hard to do because each provider supplies different set of schema
info.

2. how do I do it for Sql Server 2000, Sql Server 2005, and Access
OLEDB provider for SQL server may better fit the need.
(see "Microsoft SQL Server OLEDB Provider" and "Microsoft Jet OLEDB
Provider" sections in the article
http://msdn.microsoft.com/en-us/library/ms254969(VS.80).aspx).

1) Enumerate all user tables in a database.

We can call conn.GetSchema("Tables"); and filter the outputs by
TABLE_TYPE=="TABLE"

2) Enumerate all tables (user & system) in a database.

We can call conn.GetSchema("Tables"); and filter the outputs by
TABLE_TYPE=="TABLE" OR TABLE_TYPE=="SYSTEM TABLE"

3) Enumerate all user views in a database.

We can call conn.GetSchema("Tables"); and filter the outputs by
TABLE_TYPE=="VIEW"

4) Enumerate all views (user & system) in a database.

We can call conn.GetSchema("Tables"); and filter the outputs by
TABLE_TYPE=="VIEW" OR TABLE_TYPE=="SYSTEM VIEW"

5) Enumerate all columns in a table or view.

We can call conn.GetSchema("Columns"); and filter the outputs by
TABLE_NAME=="our table/view name"

6) For a column, get it's data type.

The DATA_TYPE field of question 5) provides the data type info of the
column.

7) Enumerate all user stored procedures in a database
8) Enumerate all stored procedures (user & system) in a database.

We can call conn.GetSchema("Procedures"); to get all the stored procedures.
As far as I know, there's no strict criteria to distinguish the user/system
stored procedure. A possible solution is to filter by SP name because all
the system SPs starts with "dt_" or "sp_".

9) For a stored procedure, get all parameters and their data type.

conn.GetSchema("ProcedureParameters"); and filter the outputs by
PROCEDURE_NAME="our procedure name"

10) For all objects - get the description of it in the metadata.

Do you mean MetaDataCollections?
http://msdn.microsoft.com/en-us/library/ms254501(VS.80).aspx

Apart from the above, OLEDB provider has an additional set of methods to
retrieve the schema info:
http://support.microsoft.com/kb/309681/en-us

If you have any other questions or concerns, please DON'T hesitate to tell
me.

Regards,
Jialiang Ge (jia...@online.microsoft.com, remove 'online.')
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
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[David Thielen]

Thank you the GetOleDbSchemaTable call helps a bunch for OleDb. For
ODBC it looks like we're stuck with it being different for every
driver - which isn't much help when hitting a driver we haven't seen
before.

Oh well, it's a very old spec so it makes sense that it isn't that
complete.

thanks - dave

[Pak-Ming Cheung [MSFT]]

For ODBC, there are some meta-data functions (or so-called catalog functions):
http://msdn.microsoft.com/en-us/library/ms712628.aspx

For example, if you want to get all table information, you can use the API
SQLTables:
http://msdn.microsoft.com/en-us/library/ms711831(VS.85).aspx
Note that field TABLE_TYPE in the result set. This tells you whether a table
is system or user.

Let's try those catalog APIs and see whether this can solve your problem.

Ming.
MDAC Team, Microsoft.

[David Thielen]

For tables that works great.

For views we need to do:

DataTable schemaTable =
conn.GetSchema("views");

foreach (DataRow rowOn in
schemaTable.Rows)
if
((((string)rowOn["TABLE_TYPE"]).ToUpper() == "VIEW") &&

(((string)rowOn["TABLE_SCHEM"]).ToUpper() != "INFORMATION_SCHEMA") &&

(((string)rowOn["TABLE_SCHEM"]).ToUpper() != "SYS"))
rtn.Add(new
WrView((string)rowOn["TABLE_NAME"], "", false));

For stored procedures we need to do:
DataTable schemaTable =
conn.GetSchema("procedures");
foreach (DataRow rowOn in
schemaTable.Rows)
{
if
((((string)rowOn["PROCEDURE_SCHEM"]).ToUpper() ==
"INFORMATION_SCHEMA") ||

(((string)rowOn["PROCEDURE_SCHEM"]).ToUpper() == "SYS"))
continue;

string name =
(string)rowOn["PROCEDURE_NAME"];
if (name.StartsWith("dt_")) //
only way I could find to skip system ones
continue;
if (name.IndexOf(';') != -1)
name =
name.Substring(0, name.IndexOf(';'));
rtn.Add(new
WrStoredProcedure(name, "", false));
}

And for both views & stored procedures we don't know how well that
will work with all ODBC drivers as INFORMATION_SCHEMA is a SqlServer
table.

thanks - dave

[corem...@gmail.com]

INFORMATION_SCHEMA is part of one of the newer ANSI SQL standards. (SQL Server & Oracle 8i + support querying on this in one form or another).

For Access, you can always query "msysObjects" and "msysUsers" tables...