数据|数据库在编写有关数据库方面的C#程序时，经常需要知道数据库的表中各字段的以下信息：
　　1. 用于OracleParameter(或SqlParameter,...)中的字段和属性的数据库特定的数据类型。
　　2. 其对应的.NET数据类型。
　　如下面的程序片断所示：

using (OracleConnection conn = new OracleConnection(Pub.ConnString))
{
conn.Open();
OracleCommand comm = new OracleCommand(
"SELECT trdate,txcode,drcrf,amount,balance,tellerno,txnote,zoneno,nodeno FROM detail "+
"WHERE accno=:accno AND currtype=:currtype ORDER BY accno,currtype,trdate,seqno", conn);
comm.Parameters.Add("accno", OracleDbType.Int64).Value = long.Parse(acc.Substring(4,13));
comm.Parameters.Add("currtype", OracleDbType.Int16).Value = curr;
using (OracleDataReader r = comm.ExecuteReader())
{
for (cnt = 0; r.Read(); cnt++)
{
DataRow dr = dt.NewRow();
dr["TrDate"] = r.GetDateTime(0);
dr["Txcode"] = r.GetInt32(1);
dr["Drcrf"] = IcbcEtc.GetDrcrfString(r.GetInt16(2));
dr["Amount"] = r.GetInt64(3) / R;
dr["Balance"] = r.GetInt64(4) / R;
dr["Tellerno"] = r.GetInt32(5);
dr["TxNote"] = r.GetString(6);
dr["Zoneno"] = r.GetInt32(7);
dr["Nodeno"] = r.GetInt32(8);
dr["Txname"] = DbTrxCode.GetNewName((int)dr["Txcode"]);
dt.Rows.Add(dr);
}
}
}

　　为此，我编写了一个小工具，其应用示例如下：

　　这里是源程序(ODP.NET版)，需要下载“”，其命名空间是: Oracle.DataAccess.Client。

System;

System.Data;

System.Text;

System.Windows.Forms;

System.Drawing;

Oracle.DataAccess.Client;

Skyiv.Util.Odpnet

{
classOdpnetDlg:Form
{
LabellblTable;
TextBoxtbxConn;
TextBoxtbxSql;
TextBoxtbxMsg;
ButtonbtnSubmit;
CheckBoxchkStru;
DataGriddgOut;
stringstrConn="DataSource=ora-m38;UserID=test;Password=pssw0rd";

publicOdpnetDlg()
{
SuspendLayout();

btnSubmit=newButton();
btnSubmit.Text="执行";
btnSubmit.Location=newPoint(10,420);
btnSubmit.Size=newSize(60,24);
btnSubmit.Click+=newEventHandler(Submit_Click);
btnSubmit.Anchor=(AnchorStyles.Bottom|AnchorStyles.Left);

chkStru=newCheckBox();
chkStru.Text="结构";
chkStru.Location=newPoint(80,420);
chkStru.Size=newSize(60,24);
chkStru.Anchor=(AnchorStyles.Bottom|AnchorStyles.Left);

lblTable=newLabel();
lblTable.Text="数据源";
lblTable.Location=newPoint(12,460);
lblTable.Size=newSize(70,24);
lblTable.Anchor=(AnchorStyles.Bottom|AnchorStyles.Left);

tbxConn=newTextBox();
tbxConn.Text=strConn;
tbxConn.Location=newPoint(83,456);
tbxConn.Size=newSize(626,20);
tbxConn.Anchor=(AnchorStyles.Bottom|AnchorStyles.Left|AnchorStyles.Right);

tbxSql=newTextBox();
tbxSql.Text="select*\r\nfromv$version\r\n";
tbxSql.Location=newPoint(10,10);
tbxSql.Size=newSize(240,200);
tbxSql.Multiline=true;
tbxSql.ScrollBars=ScrollBars.Both;
tbxSql.AcceptsReturn=true;
tbxSql.WordWrap=true;
tbxSql.Anchor=(AnchorStyles.Top|AnchorStyles.Left);

tbxMsg=newTextBox();
tbxMsg.Location=newPoint(10,220);
tbxMsg.Size=newSize(240,190);
tbxMsg.Multiline=true;
tbxMsg.ScrollBars=ScrollBars.Both;
tbxMsg.AcceptsReturn=true;
tbxMsg.WordWrap=true;
tbxMsg.Anchor=(AnchorStyles.Top|AnchorStyles.Bottom|AnchorStyles.Left);

dgOut=newDataGrid();
dgOut.Location=newPoint(260,10);
dgOut.Size=newSize(450,436);
dgOut.CaptionVisible=false;
dgOut.ReadOnly=true;
dgOut.Anchor=(AnchorStyles.Top|AnchorStyles.Bottom|AnchorStyles.Left|AnchorStyles.Right);

Controls.AddRange(newControl[]{btnSubmit,chkStru,lblTable,tbxSql,tbxMsg,tbxConn,dgOut});
Text="数据库查询(ODPNET)";
ClientSize=newSize(720,490);
WindowState=FormWindowState.Maximized;

ResumeLayout(false);
}

voidDisplayError(Exceptionex)
{
StringBuildersb=newStringBuilder();
while(ex!=null)
{
sb.Append(">");
sb.Append(ex.GetType());
sb.Append(Environment.NewLine);
OracleExceptione=exasOracleException;
if(e!=null)
{
for(inti=0;i<e.Errors.Count;i++)sb.AppendFormat(
"Index:{1}{0}Message:{2}{0}DataSource:{3}{0}Source:{4}{0}Number:{5}{0}Procedure:{6}{0}",Environment.NewLine,
i,e.Errors[i].Message,e.Errors[i].DataSource,e.Errors[i].Source,e.Errors[i].Number,e.Errors[i].Procedure
);
}
elsesb.Append(ex.Message);
sb.Append(Environment.NewLine);
ex=ex.InnerException;
}
tbxMsg.Text=sb.ToString();
}

voidSubmit_Click(objectsender,EventArgse)
{
btnSubmit.Enabled=false;
stringsql=tbxSql.Text.Trim();
if(sql.Length==0)return;
try
{
introws=-2;
stringstrType="查询";
using(OracleConnectionconn=newOracleConnection(tbxConn.Text))
{
conn.Open();
OracleCommandcomm=newOracleCommand(sql,conn);
if(!isQuery(sql))
{
strType="非查询";
rows=comm.ExecuteNonQuery();
}
elseif(chkStru.Checked)
{
strType="表结构";
dgOut.DataSource=RunQueryTableStruct(comm);
}
elsedgOut.DataSource=RunQueryTableData(comm);
}
tbxMsg.Text="运行SQL语句完毕("+strType+")";
if(rows>=0)tbxMsg.Text="受影响的行数:"+rows.ToString("N0");
}
catch(Exceptionex)
{
DisplayError(ex);
}
btnSubmit.Enabled=true;
}

boolisQuery(stringsql)
{
returnsql.Substring(0,6).ToUpper()=="SELECT";
}

privateDataViewRunQueryTableData(OracleCommandcomm)
{
OracleDataAdapterda=newOracleDataAdapter();
da.SelectCommand=comm;
DataSetds=newDataSet();
da.Fill(ds);
returnds.Tables[0].DefaultView;
}

privateDataViewRunQueryTableStruct(OracleCommandcomm)
{
DataTabledt=newDataTable();
dt.Columns.Add("#",typeof(int));
dt.Columns.Add("字段名",typeof(string));
dt.Columns.Add("数据类型",typeof(string));
dt.Columns.Ad, d("源数据类型",typeof(string));
dt.Columns.Add("大小",typeof(string));
dt.Columns.Add("备注",typeof(string));
using(OracleDataReaderr=comm.ExecuteReader(CommandBehavior.KeyInfo))
{
DataTabledt0=r.GetSchemaTable();
//returndt0.DefaultView;
foreach(DataRowdr0indt0.Rows)
{
DataRowdr=dt.NewRow();
dr[0]=(int)dr0["ColumnOrdinal"];
dr[1]=(string)dr0["ColumnName"];
dr[2]=GetBriefType(dr0["DataType"]);
dr[3]=((OracleDbType)dr0["ProviderType"]).ToString();
dr[4]=string.Format(
"({0},{1}){2}",GetInt16(dr0["NumericPrecision"]),GetInt16(dr0["NumericScale"]),(int)dr0["ColumnSize"]
);
dr[5]=string.Format(
"{0}{1}{2}{3}{4}{5}{6}{7}{8}{9}",
isTrue(dr0["AllowDBNull"])?"AllowDBNull":"",
isTrue(dr0["IsKey"])?"Key":"",
isTrue(dr0["IsUnique"])?"Unique":"",
isTrue(dr0["IsLong"])?"Long":"",
isTrue(dr0["IsReadOnly"])?"ReadOnly":"",
isTrue(dr0["IsRowID"])?"RowID":"",
isTrue(dr0["IsAliased"])?"Aliased":"",
isTrue(dr0["IsByteSemantic"])?"ByteSemantic":"",
isTrue(dr0["IsExpression"])?"Expression":"",
isTrue(dr0["IsHidden"])?"Hidden":""
);
dt.Rows.Add(dr);
}
}
returndt.DefaultView;
}

boolisTrue(objectobj)
{
if(obj==DBNull.Value)returnfalse;
return(bool)obj;
}

shortGetInt16(objectobj)
{
if(obj==DBNull.Value)return-1;
elsereturn(short)obj;
}

stringGetBriefType(objectobj)
{
strings=(objasType).ToString();
if(string.CompareOrdinal(s,0,"System.",0,7)==0)s=s.Substring(7);
returns;
}

staticvoidMain()
{
Application.Run(newOdpnetDlg());
}
}
}

　　此外，该程序还有以下各种版本：
System.Data.OracleClient;
System.Data.SqlClient;
System.Data.OleDb;
System.Data.Odbc;
　　限于篇幅，这里不就贴出源程序了，各位可以自己在ODP.NET版本的基础上稍做修改就行了。
　　同样是Oracle数据库，使用Oracle.DataAccess.Client和System.Data.OracleClient还是有区别的，请参阅:
“”
　　例如，对于数据库中的NUMBER类型，Oracle.DataAccess.Client对应的.NET类型可以是byte、short、int、long、decimal等类型，而System.Data.OracleClient一般都对应为decimal类型。