C # solutions that do not operate on the Paradox database

With Delphi with the Database Desktop tool to open the db file, edit the table, to a field index on it, will generate a XXX.PX index file

Refer to the following document, where 4 is the second one.

http://support.microsoft.com/kb/q175168/

4. The last question and workaround applies to all SQL data sources. SQL statements that violate referential integrity of the database can cause this error to occur. The following are some of the most common failed queries:

• The simplest set of queries is the following query that you cannot change: A crosstab query with a UniqueValue property set to Yes, a SQL pass-through query, a federated query, or an update (that is, a build table) action query.

• Another very common reason is that the index of the linked ODBC table that the join contains is not unique. In this case, SQL cannot guarantee that the records in the table are unique, and that the values of the fields in the table will change with the query.

• There is a reason that there are reliable alternatives. If you try to update the join field on the "one" side of the "One-to-many" query, the operation will fail unless you enable cascading updates. Because of this, you can delegate referential integrity to the JET engine.

Reference Code

string ConnectionString = @"Driver={Microsoft Paradox Driver (*.db )};DriverID=538;Fil=Paradox 5.X;DefaultDir=C:Paradox;Dbq=C:Paradox;CollatingSequence=ASCII;PWD=;";
　　　　　　using (System.Data.Odbc.OdbcConnection conn = new System.Data.Odbc.OdbcConnection(ConnectionString))
　　　　　　...{
　　　　　　　　conn.Open();
　　　　　　　　using (System.Data.Odbc.OdbcCommand command = conn.CreateCommand())
　　　　　　　　...{
　　　　　　　　　　command.CommandText = " update test set aa=14";
　　　　　　　　　　command.ExecuteNonQuery();
　　　　　　　　　
　　　　　　　　　　command.CommandText = "select * from test";
　　　　　　　　　　Console.WriteLine(command.ExecuteScalar());
　　　　　　　　}
　　　　　　}