Csharp/C Sharp/Database ADO.net/DataSet
Содержание
- 1 DataSet Delete
- 2 DataSet Read
- 3 Finding Data
- 4 For each row in DataSet, reference the column data by column name
- 5 How to perform a SELECT statement and store the returned rows in a DataSet object
- 6 how to write and read XML files
- 7 Open the XML file and read into a DataSet
- 8 Populate a DataSet object with multiple DataTable objects
- 9 Populate a DataSet object with multiple DataTable objects by changing the CommandText property of a DataAdapter object"s SelectCommand
- 10 Populate a DataSet with multiple DataTable objects using multiple SELECT statements
- 11 Print DataSet out
- 12 Read data from DataSet
- 13 ReadXml
- 14 Use DataViewManager to wrap DataSet
- 15 Use the Merge() method
- 16 Using Datasets
- 17 Using Multi Tabled Datasets
DataSet Delete
<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; using System.Data; using System.Data.SqlClient; class Program {
static void Main(string[] args) {
DataSet theCarsInventory = new DataSet();
SqlConnection cn = new SqlConnection("server=(local);User ID=sa;Pwd=;database=Cars");
SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM Inventory", cn);
SqlCommandBuilder invBuilder = new SqlCommandBuilder(da);
da.Fill(theCarsInventory, "Inventory");
PrintDataSet(theCarsInventory);
try {
theCarsInventory.Tables["Inventory"].Rows[1].Delete();
da.Update(theCarsInventory, "Inventory");
} catch (Exception e) {
Console.WriteLine(e.Message);
}
theCarsInventory = new DataSet();
da.Fill(theCarsInventory, "Inventory");
PrintDataSet(theCarsInventory);
}
static void PrintDataSet(DataSet ds) {
Console.WriteLine("Tables in "{0}" DataSet.\n", ds.DataSetName);
foreach (DataTable dt in ds.Tables) {
Console.WriteLine("{0} Table.\n", dt.TableName);
for (int curCol = 0; curCol < dt.Columns.Count; curCol++) {
Console.Write(dt.Columns[curCol].ColumnName.Trim() + "\t");
}
for (int curRow = 0; curRow < dt.Rows.Count; curRow++) {
for (int curCol = 0; curCol < dt.Columns.Count; curCol++) {
Console.Write(dt.Rows[curRow][curCol].ToString().Trim() + "\t");
}
Console.WriteLine();
}
}
}
}
</source>
DataSet Read
<source lang="csharp"> using System; using System.Data; // Use ADO.NET namespace using System.Data.SqlClient; // Use SQL Server data provider namespace using System.Collections.Generic; using System.Text; class Program {
static void Main(string[] args) {
SqlConnection thisConnection = new SqlConnection(
@"Server=(local)\sqlexpress;Integrated Security=True;" +
"Database=northwind");
SqlDataAdapter thisAdapter = new SqlDataAdapter(
"SELECT CustomerID, ContactName FROM Customers", thisConnection);
DataSet thisDataSet = new DataSet();
thisAdapter.Fill(thisDataSet, "Customers");
foreach (DataRow theRow in thisDataSet.Tables["Customers"].Rows) {
Console.WriteLine(theRow["CustomerID"] + "\t" +
theRow["ContactName"]);
}
thisConnection.Close();
}
}
</source>
Finding Data
<source lang="csharp">
using System; using System.Data; using System.Data.SqlClient; using System.Collections.Generic; using System.Text; class Program {
static void Main(string[] args) {
SqlConnection thisConnection = new SqlConnection(
@"Server=(local)\sqlexpress;Integrated Security=True;" +
"Database=northwind");
SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT CustomerID, CompanyName FROM Customers", thisConnection);
SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);
DataSet thisDataSet = new DataSet();
thisAdapter.Fill(thisDataSet, "Customers");
Console.WriteLine("# rows before change: {0}",thisDataSet.Tables["Customers"].Rows.Count);
DataColumn[] keys = new DataColumn[1];
keys[0] = thisDataSet.Tables["Customers"].Columns["CustomerID"];
thisDataSet.Tables["Customers"].PrimaryKey = keys;
DataRow findRow = thisDataSet.Tables["Customers"].Rows.Find("AAA");
if (findRow == null) {
DataRow thisRow = thisDataSet.Tables["Customers"].NewRow();
thisRow["CustomerID"] = "AAA";
thisRow["CompanyName"] = "AAA Ltd.";
thisDataSet.Tables["Customers"].Rows.Add(thisRow);
if ((findRow = thisDataSet.Tables["Customers"].Rows.Find("AAA")) != null) {
Console.WriteLine("added");
}
} else {
Console.WriteLine("AAA already present in database");
}
thisAdapter.Update(thisDataSet, "Customers");
Console.WriteLine("# rows after change: {0}",thisDataSet.Tables["Customers"].Rows.Count);
thisConnection.Close();
}
}
</source>
For each row in DataSet, reference the column data by column name
<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class Class1{
static void Main(string[] args){
SqlConnection thisConnection = new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI");
SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT ID, FirstName FROM Employee", thisConnection);
DataSet thisDataSet = new DataSet();
thisAdapter.Fill(thisDataSet, "Employee");
foreach (DataRow theRow in thisDataSet.Tables["Employee"].Rows)
{
Console.WriteLine(theRow["ID"] + "\t" + theRow["FirstName"]);
}
}
}
</source>
How to perform a SELECT statement and store the returned rows in a DataSet object
<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class SelectIntoDataSet {
public static void Main() {
string connectionString = "server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI";
SqlConnection mySqlConnection = new SqlConnection(connectionString);
string selectString = "SELECT TOP 10 ID, FirstName, LastName FROM Employee ORDER BY ID";
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText = selectString;
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
Console.WriteLine("Retrieving rows from the Employee table");
mySqlDataAdapter.Fill(myDataSet, "Employee");
mySqlConnection.Close();
DataTable myDataTable = myDataSet.Tables["Employee"];
foreach (DataRow myDataRow in myDataTable.Rows)
{
Console.WriteLine("ID = "+ myDataRow["ID"]);
Console.WriteLine("FirstName = "+ myDataRow["FirstName"]);
Console.WriteLine("LastName = "+ myDataRow["LastName"]);
}
}
}
</source>
how to write and read XML files
<source lang="csharp">
using System;
using System.Data;
using System.Data.SqlClient;
class WriteAndReadXML {
public static void Main() {
SqlConnection mySqlConnection = new SqlConnection("server=localhost;database=Northwind;uid=sa;pwd=sa");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText =
"SELECT TOP 2 CustomerID, CompanyName, ContactName, " +
"Address " +
"FROM Customers " +
"ORDER BY CustomerID";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
mySqlDataAdapter.Fill(myDataSet, "Customers");
mySqlConnection.Close();
myDataSet.WriteXml("myXmlFile.xml");
myDataSet.WriteXml("myXmlFile2.xml", XmlWriteMode.WriteSchema);
myDataSet.WriteXmlSchema("myXmlSchemaFile.xml");
myDataSet.Clear();
myDataSet.ReadXml("myXmlFile.xml");
DataTable myDataTable = myDataSet.Tables["Customers"];
foreach (DataRow myDataRow in myDataTable.Rows) {
Console.WriteLine("CustomerID = " + myDataRow["CustomerID"]);
Console.WriteLine("CompanyName = " + myDataRow["CompanyName"]);
Console.WriteLine("ContactName = " + myDataRow["ContactName"]);
Console.WriteLine("Address = " + myDataRow["Address"]);
}
}
}
</source>
Open the XML file and read into a DataSet
<source lang="csharp">
using System; using System.IO; using System.Data; public class MainClass {
static void Main(string[] args) {
if (args.Length != 1)
return;
FileStream fs = new FileStream(args[0], FileMode.Open);
DataSet ds = new DataSet();
ds.ReadXml(fs);
// Use a DataTable to display the members.
DataTable mt = ds.Tables["member"];
for (int row = 0; row < mt.Rows.Count; row++) {
for (int col = 0; col < mt.Columns.Count - 1; col++) {
Console.WriteLine("{0,-10}{1}",
mt.Columns[col].Caption,
mt.Rows[row][col].ToString().Trim());
}
Console.WriteLine();
}
fs.Close();
}
}
</source>
Populate a DataSet object with multiple DataTable objects
<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class MultipleDataTables2 {
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText =
"SELECT TOP 2 ID, FirstName, LastName " +
"FROM Employee " +
"ORDER BY ID";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
int numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Employee");
Console.WriteLine("numberOfRows = " + numberOfRows);
mySqlDataAdapter.SelectCommand.rumandText =
"SELECT ID, Name " +
"FROM Customers " +
"WHERE ID = "001"";
numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Customers");
Console.WriteLine("numberOfRows = " + numberOfRows);
mySqlConnection.Close();
foreach (DataTable myDataTable in myDataSet.Tables) {
Console.WriteLine("\nReading from the " +
myDataTable.TableName + "DataTable");
foreach (DataRow myDataRow in myDataTable.Rows)
{
foreach (DataColumn myDataColumn in myDataTable.Columns)
{
Console.WriteLine(myDataColumn + "= " +
myDataRow[myDataColumn]);
}
}
}
}
}
</source>
Populate a DataSet object with multiple DataTable objects by changing the CommandText property of a DataAdapter object"s SelectCommand
<source lang="csharp">
using System; using System.Data; using System.Data.SqlClient; class MultipleDataTables2 {
public static void Main() {
SqlConnection mySqlConnection = new SqlConnection("server=localhost;database=Northwind;uid=sa;pwd=sa");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText = "SELECT TOP 2 ProductID, ProductName, UnitPrice FROM Products ORDER BY ProductID";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
int numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Products");
Console.WriteLine("numberOfRows = " + numberOfRows);
mySqlDataAdapter.SelectCommand.rumandText = "SELECT CustomerID, CompanyName FROM Customers WHERE CustomerID = "ALFKI"";
numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Customers");
Console.WriteLine("numberOfRows = " + numberOfRows);
mySqlConnection.Close();
foreach (DataTable myDataTable in myDataSet.Tables) {
Console.WriteLine("\nReading from the " + myDataTable.TableName + " DataTable");
foreach (DataRow myDataRow in myDataTable.Rows) {
foreach (DataColumn myDataColumn in
myDataTable.Columns) {
Console.WriteLine(myDataColumn + " = " + myDataRow[myDataColumn]);
}
}
}
}
}
</source>
Populate a DataSet with multiple DataTable objects using multiple SELECT statements
<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class MultipleDataTables {
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText =
"SELECT TOP 2 ID, FirstName, LastName " +
"FROM Employee " +
"ORDER BY ID;" +
"SELECT ID, LastName " +
"FROM MyEmployee " +
"WHERE ID = 9;";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
int numberOfRows = mySqlDataAdapter.Fill(myDataSet);
Console.WriteLine("numberOfRows = " + numberOfRows);
mySqlConnection.Close();
myDataSet.Tables["Table"].TableName = "Employee";
myDataSet.Tables["Table1"].TableName = "MyEmployee";
foreach (DataTable myDataTable in myDataSet.Tables) {
Console.WriteLine("\nReading from the " +
myDataTable.TableName + "DataTable");
foreach (DataRow myDataRow in myDataTable.Rows)
{
foreach (DataColumn myDataColumn in myDataTable.Columns)
{
Console.WriteLine(myDataColumn + "= " +
myDataRow[myDataColumn]);
}
}
}
}
}
</source>
Print DataSet out
<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; using System.Data; using System.Data.SqlClient; using System.Data.rumon; class Program {
static void Main(string[] args) {
string cnStr = "uid=sa;pwd=;Initial Catalog=yourDatabase;Data Source=(local)";
DataSet myDS = new DataSet("Cars");
SqlDataAdapter dAdapt = new SqlDataAdapter("Select * From Inventory", cnStr);
DataTableMapping custMap = dAdapt.TableMappings.Add("Inventory", "Current Inventory");
custMap.ColumnMappings.Add("CarID", "Car ID");
custMap.ColumnMappings.Add("PetName", "Name of Car");
try {
dAdapt.Fill(myDS, "Inventory");
} catch (Exception ex) {
Console.WriteLine(ex.Message);
}
PrintDataSet(myDS);
}
static void PrintDataSet(DataSet ds) {
Console.WriteLine("Tables in "{0}" DataSet.\n", ds.DataSetName);
foreach (DataTable dt in ds.Tables) {
Console.WriteLine("{0} Table.\n", dt.TableName);
for (int curCol = 0; curCol < dt.Columns.Count; curCol++) {
Console.Write(dt.Columns[curCol].ColumnName.Trim() + "\t");
}
for (int curRow = 0; curRow < dt.Rows.Count; curRow++) {
for (int curCol = 0; curCol < dt.Columns.Count; curCol++) {
Console.Write(dt.Rows[curRow][curCol].ToString().Trim() + "\t");
}
Console.WriteLine();
}
}
}
}
</source>
Read data from DataSet
<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class PopDataset {
static void Main()
{
string connString = "server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI";
string sql = @"select * from employee";
SqlConnection conn = new SqlConnection(connString);
try
{
conn.Open();
SqlDataAdapter da = new SqlDataAdapter(sql, conn);
DataSet ds = new DataSet();
da.Fill(ds, "employee");
DataTable dt = ds.Tables["employee"];
foreach (DataRow row in dt.Rows)
{
foreach (DataColumn col in dt.Columns)
Console.WriteLine(row[col]);
Console.WriteLine("".PadLeft(20, "="));
}
}
catch(Exception e)
{
Console.WriteLine("Error: " + e);
}
finally
{
conn.Close();
}
}
}
</source>
ReadXml
<source lang="csharp">
using System; using System.Data; using System.Collections.Generic; using System.Text; class Program {
static void Main(string[] args) {
DataSet thisDataSet = new DataSet();
thisDataSet.ReadXml("nwinddata.xml");
foreach (DataRow custRow in thisDataSet.Tables["Customers"].Rows) {
Console.WriteLine("Customer ID: " + custRow["CustomerID"] +
" Name: " + custRow["CompanyName"]);
}
Console.WriteLine("Table created by ReadXml is called {0}",
thisDataSet.Tables[0].TableName);
}
}
</source>
Use DataViewManager to wrap DataSet
<source lang="csharp"> using System; using System.Collections.Generic; using System.ruponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Configuration; using System.Data.SqlClient; public class Form1 : Form {
public Form1() {
InitializeComponent();
}
private void getData_Click(object sender, EventArgs e) {
string orders = "SELECT * FROM Orders";
string customers = "SELECT * FROM Customers";
using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["northwind"].ConnectionString)) {
SqlDataAdapter da = new SqlDataAdapter(orders, con);
DataSet ds = new DataSet();
da.Fill(ds, "Orders");
da = new SqlDataAdapter(customers, con);
da.Fill(ds, "Customers");
ds.Relations.Add("CustomerOrders",
ds.Tables["Customers"].Columns["CustomerID"],
ds.Tables["Orders"].Columns["CustomerID"]);
DataViewManager dvm = new DataViewManager(ds);
dvm.DataViewSettings["Customers"].RowFilter = "Country="UK"";
dataGrid1.SetDataBinding(dvm, "Customers");
}
}
private void InitializeComponent() {
this.dataGrid1 = new System.Windows.Forms.DataGrid();
this.getData = new System.Windows.Forms.Button();
((System.ruponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
this.SuspendLayout();
this.dataGrid1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
| System.Windows.Forms.AnchorStyles.Left)
| System.Windows.Forms.AnchorStyles.Right)));
this.dataGrid1.DataMember = "";
this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
this.dataGrid1.Location = new System.Drawing.Point(13, 13);
this.dataGrid1.Size = new System.Drawing.Size(488, 374);
this.getData.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
this.getData.Location = new System.Drawing.Point(426, 393);
this.getData.Size = new System.Drawing.Size(75, 23);
this.getData.Text = "Get Data";
this.getData.UseVisualStyleBackColor = true;
this.getData.Click += new System.EventHandler(this.getData_Click);
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(513, 428);
this.Controls.Add(this.getData);
this.Controls.Add(this.dataGrid1);
((System.ruponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
this.ResumeLayout(false);
}
private System.Windows.Forms.DataGrid dataGrid1;
private System.Windows.Forms.Button getData;
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
</source>
Use the Merge() method
<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class Merge {
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText =
"SELECT ID, FirstName, LastName, Address " +
"FROM Customers " +
"WHERE ID IN ("001", "002", "003")";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
mySqlDataAdapter.Fill(myDataSet, "Customers");
mySqlCommand.rumandText =
"SELECT ID, FirstName, LastName, Address " +
"FROM Customers " +
"WHERE CustomerID IN ("008", "009")";
DataSet myDataSet2 = new DataSet();
mySqlDataAdapter.Fill(myDataSet2, "Customers2");
mySqlCommand.rumandText =
"SELECT TOP 5 ProductID, ProductName, UnitPrice " +
"FROM Products " +
"ORDER BY ProductID";
DataSet myDataSet3 = new DataSet();
mySqlDataAdapter.Fill(myDataSet3, "Products");
mySqlConnection.Close();
myDataSet.Merge(myDataSet2);
myDataSet.Merge(myDataSet3, true, MissingSchemaAction.Add);
foreach (DataTable myDataTable in myDataSet.Tables) {
Console.WriteLine("\nReading from the " + myDataTable + "DataTable");
foreach (DataRow myDataRow in myDataTable.Rows) {
foreach (DataColumn myDataColumn in myDataTable.Columns) {
Console.WriteLine(myDataColumn + "= " + myDataRow[myDataColumn]);
}
}
}
}
}
</source>
Using Datasets
<source lang="csharp"> /*
* C# Programmers Pocket Consultant * Author: Gregory S. MacBeth * Email: gmacbeth@comporium.net * Create Date: June 27, 2003 * Last Modified Date: * Version: 1 */
using System; using System.Data; using System.Data.SqlClient; namespace Client.Chapter_13___ADO.NET {
public class UsingDatasets
{
static void Main(string[] args)
{
SqlConnection MyConnection = new SqlConnection(@"Data Source=(local); Initial Catalog = CaseManager; Integrated Security=true");
SqlDataAdapter MyAdapter = new SqlDataAdapter("SELECT * FROM CaseInfo", MyConnection);
DataSet MyDataSet = new DataSet();
MyAdapter.Fill(MyDataSet, "MyTable");
MyDataSet.WriteXml(@"c:\MyDatSet.xml");
}
}
}
</source>
Using Multi Tabled Datasets
<source lang="csharp"> /*
* C# Programmers Pocket Consultant * Author: Gregory S. MacBeth * Email: gmacbeth@comporium.net * Create Date: June 27, 2003 * Last Modified Date: * Version: 1 */
using System; using System.Data; using System.Data.OleDb; namespace Client.Chapter_13___ADO.NET {
public class UsingMultiTabledDatasets
{
static void Main(string[] args)
{
OleDbConnection MyConnection = new OleDbConnection(@"Provider=Microsft.Jet.OLEDB.4.0; Data Source = c:\MyAccessDB.mdb");
OleDbDataAdapter MyAdapter = new OleDbDataAdapter("SELECT Column1, Column2, Column3 FROM MyTable", MyConnection);
DataSet MyDataSet = new DataSet();
MyAdapter.Fill(MyDataSet, "MyTable");
foreach (DataTable MyTable in MyDataSet.Tables)
{
foreach (DataColumn MyColumn in MyTable.Columns)
{
foreach (DataRow MyRow in MyTable.Rows)
{
}
}
}
}
}
}
</source>
