在C＃中合并数据表

Question

I have 2 identically constructed datatables. The difference is where they get their data.

public DataTable dtPubSearchResultsFromTable(string sqlQuery)
{
    // Returns a datatable of publication search results based on data in table.
    SqlConnection con = new SqlConnection(getConnectionString());
    SqlCommand cmd = new SqlCommand(sqlQuery, con);
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    dt.Columns.Add("Pages", typeof(string));
    da.Fill(dt);
    dt.PrimaryKey = new DataColumn[] { dt.Columns["publicationID"] };

    return dt;
}

public DataTable dtPubSearchResultsFromFiles(string sqlQuery, string safeKeyword)
{
    // Returns a datatable of publication search results based on PDF files.
    SqlConnection con = new SqlConnection(getConnectionString());
    SqlCommand cmd = new SqlCommand(sqlQuery, con);
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    dt.Columns.Add("Pages", typeof(string));
    da.Fill(dt);
    dt.PrimaryKey = new DataColumn[] { dt.Columns["publicationID"] };

    return dt;
}

Since the second datatable is looking through PDF file for specific keywords, I populate the "Pages" column. Then, I merge the 2 datatables EXPECTING to get a list of documents where the primary key "publicationID" is only listed once and the "Pages" column is updated with the list of page numbers from the 2nd datatable. (I found this process in another question from 2011)

    var dtC = new DataTable("CombinationOfBoth");
    dtC.Columns.Add("publicationID",typeof(int));
    dtC.Columns.Add("PrimaryAuthor", typeof (string));
    dtC.Columns.Add("title", typeof (string));
    dtC.Columns.Add("rstiNumber", typeof(string));
    dtC.Columns.Add("linkToPublicationPDF", typeof(string));
    dtC.Columns.Add("publishDate", typeof(string));
    dtC.Columns.Add("approvalDate", typeof (string));
    dtC.Columns.Add("Pages", typeof(string));

    dtC.Merge(dt1,false,MissingSchemaAction.Ignore);
    dtC.Merge(dt2, false, MissingSchemaAction.Ignore);

What I ACTUALLY get is a list of all of the document records and the ones that are in BOTH datatables are listed TWICE (once without page numbers, once with page numbers).

It seems I might be using the "MissingSchemaAction" improperly.

Thanks, Bob

Answer 1

在黑暗中刺刺-在您原来的2个表中，您已经定义了主键，但是在组合的表中却没有？

Answer 2

As it turns out, I WAS using MissingSchemaAction improperly. It should have been MissingSchemaAction.Add

Answer 3

Adding a primary key to the data table that merges the dt1 and dt2 should solve that issue. Add the following line before merging:

    dtC.PrimaryKey = new DataColumn[] { dtC.Columns["publicationID"] };