开发者

Missing table in Visual FoxPro DB

I'm using VFPOLEDB to connect to an VFP database (directory of dbf files).

Once connected, I manually create a table using:

create dbf critera(field_name 开发者_Python百科c(30))

At this point, I verify a new dbf file is created in the database directory. I then try to query the new table, it should return no rows.

select * from criteria

I am presented with the following error:

File "criteria.dbf" does not exit. 

Strange, eh?

So I manually delete the DBF file (VFPOLEDB doesn't support drop) and then run the following query.

create db criteria(field_name c(30)); select * from criteria

And get no error, no results returned as expected.

What gives? Any suggestions?


First, (could be a type-o), you had

create dbf Critera  (missing the "i")

and then

select * from Criteria (has the "i")

If not that... for your connection string, are you just connecting to the PATH that the .dbf files will be located, or are you explicitly connecting to a path and database.

If just a path

string YourVFPConnectionString =
   "Provider=VFPOLEDB.1;Data Source=c:\\SomePath\\WhereDataIs\\";

Or with a specific database container

string YourVFPConnectionString =
   "Provider=VFPOLEDB.1;Data Source=c:\\SomePath\\WhereDataIs\\YourDatabase.dbc";

It might be easier to test just by pointing to the directory. The VFP OleDB provider will consider the path the root for any tables queried vs a full .dbc (database container) which could give you access to other stored procedures and such.

The OleDb doesn't support "DROP TABLE". You can still delete a file by running an ERASE "Criteria.dbf" via the OleDbCommand's ExecuteNonQuery()

As for the last one, VFP doesn't utilize the ";" as a break between statements like other SQL engines do where you could send a series of queries all together one after another. ";" in VFP is considered a "this command continues on the next line", and should have thrown an exception is it wouldn't have been able to process it.

0

上一篇:

下一篇:

精彩评论

暂无评论...
验证码 换一张
取 消

最新问答

问答排行榜