1. Naming Specification (1) The prefix in the method is not
2. MUL (1) Aggregation and Combination Differences (2) Aggregation and Generalization Difference (3) Order and Settle Items are polymerization relationships or combined relationships
3.System.data.sqltypes namespace
Definition in MSDN: system.data.sqltypes Namespace Provides classes for native data types in SQL Server. These classes provide a more secure and faster ways than other data types. Use these classes in this namespace in this name space in this name space in this name space. Since other data types are converted to SQLTypes on the scenes, they are explicitly created and used in this namespace will make the code faster.
4. Several Ways of Loop in Oracle have the following three ways: loop exit by ...; end loop;
For Num in 1..500 loop ... End loop;
While ... loop ... End loop;
When the branch of the Switch statement is more, the data driver is used.
5. Using Oracle Databases in .NET
Using system; using system.data; using system.data.oraclenet;
public class DataReaderSample {public static void Main () {string strConnString = "User ID = MY_USER; password = ****; Data Source = 12345678910111213141516"; OracleConnection conConnection = new OracleConnection (strConnString);
OracleCommand cmd = contonnection.createCommand (); cmd.commandtext = "select * from my_table2";
Try {contonnection.open ();
CMD.executeoraclescalar (); // system.data.OracleClient.Oracledataadapter DataDp = New OracleDataAdapter (CMD); OracleDataReader RedReader = cmd.executeReader ();
While (redReader.read ()) {console.writeline ("/ t {0} / t {1} / t {2} / t {3}", redreader.getstring (0), RedReader.getstring (1), RedReader.getstring (2), redReader.getstring (3)); console.readline ();} redReader.close (); // system.data.dataable dattbl = new data ("dattbl"); // datadp.fill (DATTBL);} catch (exception e) {console.write (E.MESSAGE); console.readline ();} finally {contonnection.close ();
}
problem:
(1) ORA-00162: External DBID Length 22 IS Greater Than Maximum (16)
This happens when the connection name is more than 16 characters in .Net Framework 1.1.
solve:
A. Retrofit. NET Framework 1.0 System.Data.OracleClientB. Reconfigure the connection name:
Configuration and Migration Tools-> Net Configuration Assistant configuration