数据库备份问题，急!!!

Question

deregisterDriver原来的jdbc driver，再通过配置文件或其他得到接下来用什么driver再用registerDriver装入新的。

Answer 1

没懂，可不可以说的详细写？
分别打开两个不同数据库的连接没有问题，
问题是判定字段类型，再对各个字段重新赋值很复杂(涉及道insert语句的写法)
所以问是否直接传递结果集的方式来实现记录的复制。

Answer 2

下载一个Toad之后在在窗口界面进行操作。

Answer 3

先将数据导出到一个文件，导出的实际是一系列的SQL的Insert语句，之后在另一个数据库中执行这些SQL语句就OK了。

Answer 4

参考如下代码：
Connection sourceConn = sourceDb.getJdbcConnection();
        Connection destinationConn = destinationDb.getJdbcConnection();
        ResultSet sourceRs = sourceConn.createStatement().executeQuery(trans.getQuery());
        ResultSetMetaData sourceRsMeta = sourceRs.getMetaData();
        ResultSetMetaData destinationRsMeta = destinationConn.createStatement().executeQuery("SELECT * FROM \"" + trans.destinationTab + "\" WHERE 1 = 2").getMetaData();
        String insertSQL = "INSERT INTO \"" + trans.destinationTab + "\" VALUES(";
        int sourceColCount = sourceRsMeta.getColumnCount();
        int destColCount = destinationRsMeta.getColumnCount();
      
        if(sourceColCount != destColCount) {
            throw new SQLException("源表的字段数与目标表中的字段数不相等。");
        }
        for (int i = 0;i < destColCount;i++) {
            if(i == 0) {
                insertSQL += "?";
                continue;
            }
            insertSQL += ",?";
        }
        insertSQL += ")";              // create prepared statement
        PreparedStatement pStmt = destinationConn.prepareStatement(insertSQL);
        while(sourceRs.next()) {
            for(int i = 0; i < sourceColCount;i++) {
                int sourceDataType = sourceRsMeta.getColumnType(i + 1);
                ResultSetMetaData destRsMeta = destinationConn.createStatement().executeQuery("SELECT * FROM \"" + trans.destinationTab + "\" WHERE 1 = 2").getMetaData();
                int destDataType = destRsMeta.getColumnType(i + 1);
                if(sourceRs.getObject(i + 1) == null) {
                    pStmt.setNull(i + 1,destDataType);
                    continue;
                }
                switch(sourceDataType) {
                    case java.sql.Types.ARRAY:
                        //Debugger.println("java.sql.Types.ARRAY");
                        throw new java.sql.SQLException("不支持ARRAY数据类型");
                    case java.sql.Types.BIGINT:
                        //Debugger.println("java.sql.Types.BIGINT");
                        pStmt.setObject(i + 1,new Long(sourceRs.getLong(i + 1)),destDataType);
                        break;
                    case java.sql.Types.BINARY:
                        //Debugger.println("java.sql.Types.BINARY");
                        throw new java.sql.SQLException("不支持BINARY数据类型");
                    case java.sql.Types.BIT:
                        //Debugger.println("java.sql.Types.BIT");
                        pStmt.setObject(i + 1,new Byte(sourceRs.getByte(i + 1)),destDataType);
                        break;
                        //throw new java.sql.SQLException("type BIT not supported");
                    case java.sql.Types.BLOB:
                        //Debugger.println("java.sql.Types.BLOB");
                        throw new java.sql.SQLException("不支持BLOB数据类型");
                    case java.sql.Types.CHAR:
                        //Debugger.println("java.sql.Types.CHAR");
                        pStmt.setObject(i + 1,sourceRs.getString(i + 1),destDataType);
                        break;
                    case java.sql.Types.CLOB:
                        //Debugger.println("java.sql.Types.CLOB");
                        throw new java.sql.SQLException("不支持CLOB数据类型");
                    case java.sql.Types.DATE:
                        //Debugger.println("java.sql.Types.DATE");
                        pStmt.setObject(i + 1,sourceRs.getDate(i + 1),destDataType);
                        break;
                    case java.sql.Types.DECIMAL:
                        //Debugger.println("java.sql.Types.DECIMAL");
                        pStmt.setObject(i + 1,new Float(sourceRs.getFloat(i + 1)),destDataType);
                        break;

Answer 5

接上：
  case java.sql.Types.DISTINCT:
                        //Debugger.println("java.sql.Types.DISTINCT");
                        throw new java.sql.SQLException("不支持DISTINCT数据类型");
                    case java.sql.Types.DOUBLE:
                        //Debugger.println("java.sql.Types.DOUBLE");
                        pStmt.setObject(i + 1,new Double(sourceRs.getDouble(i + 1)),destDataType);
                        break;
                    case java.sql.Types.FLOAT:
                        //Debugger.println("java.sql.Types.FLOAT");
                        pStmt.setObject(i + 1,new Float(sourceRs.getFloat(i + 1)),destDataType);
                        break;
                    case java.sql.Types.INTEGER:
                        //Debugger.println("java.sql.Types.INTEGER");
                        pStmt.setObject(i + 1,new Integer(sourceRs.getInt(i + 1)),destDataType);
                        break;
                    case java.sql.Types.JAVA_OBJECT:
                        //Debugger.println("java.sql.Types.JAVA_OBJECT");
                        throw new java.sql.SQLException("不支持JAVA_OBJECT数据类型");
                    case java.sql.Types.LONGVARBINARY://image
                        if(destDataType != java.sql.Types.LONGVARBINARY) {
                         
                            throw new java.sql.SQLException("源为image类型，目标不为image");
                        }
                     
                        pStmt.setBytes(i + 1,sourceRs.getBytes(i + 1));
                        break;
                    case java.sql.Types.LONGVARCHAR://text
                        if(destDataType != java.sql.Types.LONGVARCHAR) {
                           
                            throw new java.sql.SQLException("源为text类型，目标不为text");
                        }
                      
                        pStmt.setBytes(i + 1,sourceRs.getBytes(i + 1));
                        break;
                    case java.sql.Types.NULL:
              
                        throw new java.sql.SQLException("不支持NULL数据类型");
                    case java.sql.Types.NUMERIC:
           
                        pStmt.setObject(i + 1,new Integer(sourceRs.getInt(i + 1)),destDataType);
                        break;
                    case java.sql.Types.OTHER:
                
                        throw new java.sql.SQLException("不支持OTHER数据类型");
                    case java.sql.Types.REAL:
                    
                        pStmt.setObject(i + 1,sourceRs.getBigDecimal(i + 1),destDataType);
                        break;
                    case java.sql.Types.REF:
                   
                        throw new java.sql.SQLException("不支持REF数据类型");
                    case java.sql.Types.SMALLINT:
                     
                        pStmt.setObject(i + 1,new Integer(sourceRs.getInt(i + 1)),destDataType);
                        break;
                    case java.sql.Types.STRUCT:
                     
                        throw new java.sql.SQLException("不支持STRUCT数据类型");
                    case java.sql.Types.TIME:
                  
                        pStmt.setObject(i + 1,sourceRs.getTime(i + 1),destDataType);
                        break;
                    case java.sql.Types.TIMESTAMP:
                    
                        pStmt.setObject(i + 1,sourceRs.getTimestamp(i + 1),destDataType);
                        break;
                    case java.sql.Types.TINYINT:
                
                        pStmt.setObject(i + 1,new Short(sourceRs.getShort(i + 1)),destDataType);
                        break;
                    case java.sql.Types.VARBINARY:
  
                        throw new java.sql.SQLException("不支持VARBINARY数据类型");
                    case java.sql.Types.VARCHAR:
                        pStmt.setObject(i + 1,sourceRs.getString(i + 1),destDataType);
                        break;
                    default:
                        break;
                }
            }
            pStmt.executeUpdate();
          
        }
   

Answer 6

我那么说是为了能做一个通过配置文件，在异构的数据库中进行数据传输。所以需要用到装载/卸载不同的driver。
注：在同一个jvm中只允许一个jdbcdriver存在，所以只能动态的来切换。如果你只是为了达到数据备份的目的，完全可以使用数据库本身的导入/导出工具。