脚本组件的用法

在SSIS中，可以使用C#编写脚本，这是十分激动人心的事，能够使用C#代码，使得Script Component无所不能。

第一部分：组件简介
Script Component 有三种类型：Source, Destination and Transformation

1，每种类型的脚本，都有两种类型的参数：ReadOnly 和ReadWrite，在脚本中可以使用 this.Variables.VariableName 来获取或设置参数变量的值

示例：创建四个Variable，并传递给Script component

SSIS十分友好，在脚本中自动生成了一个子类，将Variable Name作为属性添加到子类中，引用Variable Name十分简单

public class ScriptMain : UserComponent

在脚本代码中，使用 this.Variables.VariableName 来获取或设置参数变量的值

2，可以为 Script component 指定connection ，如果在脚本中使用Ado.net，可以直接创建Ado.net connection manager，在脚本中，使用以下代码来引用connection

IDTSConnectionManager100 cnManager = this.Connections.Connection;

3，Script component 不仅有输入的Variable，而且还有output / input columns，设置output / input columns 以便输出或输入表数据

示例中增加两列Code和name，分别是string类型

第二部分：Source 组件示例

4，如果Script Component 作为Source，那么使用脚本获取数据之后，可以使用将数据逐行添加到Source 的输出buff中。

在将获得的数据集插入到output buff中时，SSIS使用的代码逻辑是：先向output buff中插入一行，然后为该行的字段赋值

　　　　DataRow dr=dt.Rows[0];

　　　　this.Output0Buffer.AddRow();
            this.Output0Buffer.Code = dr["code"].ToString();
            this.Output0Buffer.Name = dr["name"].ToString();

示例Code

    DataTable dt;
    IDTSConnectionManager100 cnManager;
    SqlConnection cnn;
    /// <summary>
    /// This method is called once, before rows begin to be processed in the data flow.
    ///
    /// You can remove this method if you don't need to do anything here.
    /// </summary>
    public override void PreExecute()
    {
        base.PreExecute();

        cnManager = this.Connections.Connection;
        cnn = (SqlConnection)cnManager.AcquireConnection(null);

        SqlCommand cmd = cnn.CreateCommand();
        cmd.CommandText = "select code,name from [dbo].[tbExcel]";
        cmd.CommandType = CommandType.Text;
        cmd.CommandTimeout = 60000;

        dt = new DataTable("dt");
        SqlDataAdapter sda = new SqlDataAdapter(cmd);
        sda.Fill(dt);
    }

    /// <summary>
    /// This method is called after all the rows have passed through this component.
    ///
    /// You can delete this method if you don't need to do anything here.
    /// </summary>
    public override void PostExecute()
    {
        base.PostExecute();
        
　　　　 cnManager.ReleaseConnection(cnn);
    }

    public override void CreateNewOutputRows()
    {
        foreach (DataRow dr in dt.Rows)
        {
            this.Output0Buffer.AddRow();
            this.Output0Buffer.Code = dr["code"].ToString();
            this.Output0Buffer.Name = dr["name"].ToString();
        }
    }

5，Script Component做为Destination，既然是作为Destination，那么肯定是有input column，用以接收上个数据源组件或转换组件的输出数据流。

示例代码如下

    SqlCommand cmd = new SqlCommand();
    DataTable dt = new DataTable("dt");
    IDTSConnectionManager100 cnManager;
    SqlConnection cnn;
    /// <summary>
    /// This method is called once, before rows begin to be processed in the data flow.
    ///
    /// You can remove this method if you don't need to do anything here.
    /// </summary>
    public override void PreExecute()
    {
        base.PreExecute();

        cnManager = this.Connections.Connection;
        cnn = (SqlConnection)cnManager.AcquireConnection(null);

        cmd.Connection = cnn;
        cmd.CommandType = CommandType.Text;
        cmd.CommandTimeout = 60000;

        dt.Columns.Add("code", typeof(string));
        dt.Columns.Add("name", typeof(string));
    }

    /// <summary>
    /// This method is called after all the rows have passed through this component.
    ///
    /// You can delete this method if you don't need to do anything here.
    /// </summary>
    public override void PostExecute()
    {
        base.PostExecute();
       
        foreach(DataRow dr in dt.Rows)
        {
            string strSql = string.Format(@"
insert into dbo.tbExcel2(code,name)
values('{0}','{1}')"
                , dr["code"].ToString(), dr["name"].ToString());

            cmd.CommandText = strSql;
            cmd.ExecuteNonQuery();
        }
        
        cnManager.ReleaseConnection(cnn);
    }

    /// <summary>
    /// This method is called once for every row that passes through the component from Input0.
    ///
    /// Example of reading a value from a column in the the row:
    ///  string zipCode = Row.ZipCode
    ///
    /// Example of writing a value to a column in the row:
    ///  Row.ZipCode = zipCode
    /// </summary>
    /// <param name="Row">The row that is currently passing through the component</param>
    public override void Input0_ProcessInputRow(Input0Buffer Row)
    {
        DataRow dr = dt.NewRow();
        dr["code"] = Row.code;
        dr["name"] = Row.name;

        dt.Rows.Add(dr);
    }

6，Script Component 作为 Transformation ，转换，顾名思义是将输入进行转换成符合要求的输出，所以，作为 Transformation 的Script Component 既有input columns，也有output columns。

示例代码如下，Input0Buffer 这个类中即包含了InputColumns，也包含了OutputColumns，InputColumns的Column是ReadOnly的，通过Input0Buffer 实例对OutputColumns进行赋值，转换数据流。

    /// <summary>
    /// This method is called once, before rows begin to be processed in the data flow.
    ///
    /// You can remove this method if you don't need to do anything here.
    /// </summary>
    public override void PreExecute()
    {
        base.PreExecute();
        /*
         * Add your code here
         */
    }

    /// <summary>
    /// This method is called after all the rows have passed through this component.
    ///
    /// You can delete this method if you don't need to do anything here.
    /// </summary>
    public override void PostExecute()
    {
        base.PostExecute();
        /*
         * Add your code here
         */
    }

    /// <summary>
    /// This method is called once for every row that passes through the component from Input0.
    ///
    /// Example of reading a value from a column in the the row:
    ///  string zipCode = Row.ZipCode
    ///
    /// Example of writing a value to a column in the row:
    ///  Row.ZipCode = zipCode
    /// </summary>
    /// <param name="Row">The row that is currently passing through the component</param>
    public override void Input0_ProcessInputRow(Input0Buffer Row)
    {
        Row.codeout = Row.code + "_out";
        Row.nameout = Row.name + "_out";
    }