使用 ADOX 将 Table 添加到 Catalog 时报“类型无效”的原因和解决方法

使用 ADOX 将 Table 添加到 Catalog 时报“类型无效”的原因和解决方法

作者：孟宪会 发表于：2010-10-21 11:12:18

使用 ADOX 创建 adDBTimeStamp 类型的字段时，会产生“类型无效”的错误提示，产生这种错误的原因是，数据库引擎 Provider 只能接受已知类型的数据类型，下面是可以接受的类型对照表：

ADOX.DataTypeEnum 类型枚举常量	Value	Jet 3.51	Jet 4.0	SQL 7.0
adBinary	128	Yes	Yes	Yes
adBoolean	11	Yes	Yes	Yes
adChar	129	Yes	No	Yes
adCurrency	6	Yes	Yes	Yes
adDate	7	Yes	Yes	No
adDouble	5	Yes	Yes	Yes
adGUID	72	Yes	Yes	Yes
adInteger	3	Yes	Yes	Yes
adLongVarBinary	205	Yes	Yes	Yes
adLongVarChar	201	Yes	No	Yes
adLongVarWChar	203	No	Yes	Yes
adNumeric	131	No	Yes (with info)*	Yes (with info)*
adSingle	4	Yes	Yes	Yes
adSmallInt	2	Yes	Yes	Yes
adUnsignedTinyInt	17	Yes	Yes	Yes
adVarBinary	204	Yes	Yes	Yes
adVarChar	200	Yes	No	Yes
adVarWChar	202	No	Yes	Yes
adWChar	130	No	Yes	Yes
adDBTimeStamp	135	No	No	Yes

* 在Microsoft Jet 4.0 和 Microsoft SQL Server 7.0 中使用 adNumeric 数据类型时，必须设置精度（precision）。

下面就是一个例子：

C# 代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using ADODB;
using ADOX;

namespace WindowsApplication2
{
     public partial class Form1 : Form
    {
         public Form1()
        {
            InitializeComponent();
        }

         private void button1_Click( object sender, EventArgs e)
        {
            CrateDBTable();

        }
         public void CrateDBTable()
        {
            String Table1 = " Category " , Table2 = " User " ;
            String ConnectStr = " Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C://db1.mdb; " ;
            ADODB.Connection cn = new ADODB.Connection();
            cn.Open(ConnectStr, null , null , - 1 );

            ADOX.Catalog cat = new ADOX.Catalog();
            cat.ActiveConnection = cn;

            ADOX.Table t; ;      
             // 对于存在的表是否要进行删除
             for ( int i = cat.Tables.Count - 1 ; i >- 1 ; i -- )
            {
                 if (cat.Tables[i].Name.Equals(Table1, StringComparison.InvariantCultureIgnoreCase)
                     || cat.Tables[i].Name.Equals(Table2, StringComparison.InvariantCultureIgnoreCase))
                {
                    t = cat.Tables[i] as ADOX.Table;
                    cat.Tables.Delete(t.Name);
                    cat.Tables.Refresh();
                }
            }
      

            ADOX.Table tbl = new ADOX.Table();
            tbl.ParentCatalog = cat;
            tbl.Name = Table1;

             // 增加一个自动增长的字段
            ADOX.Column col = new ADOX.Column();
            col.ParentCatalog = cat;
            col.Type = ADOX.DataTypeEnum.adInteger; // 必须先设置字段类型
            col.Name = " CategoryId " ;
            col.Properties[ " Jet OLEDB:Allow Zero Length " ].Value = false ;
            col.Properties[ " AutoIncrement " ].Value = true ;
            col.Properties[ " Nullable " ].Value = true ;
            tbl.Columns.Append(col, ADOX.DataTypeEnum.adInteger, 0 );
            tbl.Columns.Append( " CategoryName " , ADOX.DataTypeEnum.adVarWChar, 50 );

             // 设置主键
            tbl.Keys.Append( " PrimaryKey " , ADOX.KeyTypeEnum.adKeyPrimary, " CategoryId " , "" , "" );
            cat.Tables.Append(tbl);


             // 创建第二个表
            ADOX.Table MyTable2 = new ADOX.Table();
            MyTable2.ParentCatalog = cat;
            MyTable2.Name = Table2;

             // 增加一个自动增长的字段
            col = new ADOX.Column();
            col.ParentCatalog = cat;
            col.Type = ADOX.DataTypeEnum.adInteger; // 必须先设置字段类型
            col.Name = " UserId " ;
            col.Properties[ " Jet OLEDB:Allow Zero Length " ].Value = false ;
            col.Properties[ " AutoIncrement " ].Value = true ;
            MyTable2.Columns.Append(col, ADOX.DataTypeEnum.adInteger, 0 );
            MyTable2.Columns.Append( " UserName " , ADOX.DataTypeEnum.adVarWChar, 50 );

             // 下面这段将发生 “类型无效”的错误
             /*
            col = new ADOX.Column();
            col.ParentCatalog = cat;  
            col.Type = ADOX.DataTypeEnum.adDBTimeStamp;
            col.Properties["Nullable"].Value = true;  
            col.Name = "CreateDate";
            MyTable2.Columns.Append("CreateDate", ADOX.DataTypeEnum.adDBTimeStamp,12);
             */

             // 正确的方法
            MyTable2.Columns.Append( " CreateDate " , ADOX.DataTypeEnum.adDate, 0 );
             // 设置主键
            MyTable2.Keys.Append( " PrimaryKey " , ADOX.KeyTypeEnum.adKeyPrimary, " UserId " , "" , "" );
            cat.Tables.Append(MyTable2);
            cn.Close();
            System.Runtime.InteropServices.Marshal.ReleaseComObject(tbl);
            System.Runtime.InteropServices.Marshal.ReleaseComObject(MyTable2);
            System.Runtime.InteropServices.Marshal.ReleaseComObject(cat);
            tbl = MyTable2 = null ;
            cat = null ;
        }

    }
}