[C#基础]c#连接mysql
sql基础：http://www.w3school.com.cn/sql/index.asp
一、DataTable & DataSet
1.DataTable：表示内存中的一个数据表
2.DataSet：表示内存中的一个数据缓存，可以看作为DataTable的集合(字典)
// Put the next line into the Declarations section.
private System.Data.DataSet dataSet;
private void MakeDataTables()
{
// Run all of the functions.
MakeParentTable();
MakeChildTable();
MakeDataRelation();
BindToDataGrid();
}
private void MakeParentTable()
{
// Create a new DataTable.
System.Data.DataTable table = new DataTable("ParentTable");
// Declare variables for DataColumn and DataRow objects.
DataColumn column;
DataRow row;
// Create new DataColumn, set DataType,
// ColumnName and add to DataTable.
column = new DataColumn();
column.DataType = System.Type.GetType("System.Int32");
column.ColumnName = "id";
column.ReadOnly = true;
column.Unique = true;
// Add the Column to the DataColumnCollection.
table.Columns.Add(column);
// Create second column.
column = new DataColumn();
column.DataType = System.Type.GetType("System.String");
column.ColumnName = "ParentItem";
column.AutoIncrement = false;
column.Caption = "ParentItem";
column.ReadOnly = false;
column.Unique = false;
// Add the column to the table.
table.Columns.Add(column);
// Make the ID column the primary key column.
DataColumn[] PrimaryKeyColumns = new DataColumn[1];
PrimaryKeyColumns[0] = table.Columns["id"];
table.PrimaryKey = PrimaryKeyColumns;
// Instantiate the DataSet variable.
dataSet = new DataSet();
// Add the new DataTable to the DataSet.
dataSet.Tables.Add(table);
// Create three new DataRow objects and add
// them to the DataTable
for (int i = 0; i<= 2; i++)
{
row = table.NewRow();
row["id"] = i;
row["ParentItem"] = "ParentItem " + i;
table.Rows.Add(row);
}
}
private void MakeChildTable()
{
// Create a new DataTable.
DataTable table = new DataTable("childTable");
DataColumn column;
DataRow row;
// Create first column and add to the DataTable.
column = new DataColumn();
column.DataType= System.Type.GetType("System.Int32");
column.ColumnName = "ChildID";
column.AutoIncrement = true;
column.Caption = "ID";
column.ReadOnly = true;
column.Unique = true;
// Add the column to the DataColumnCollection.
table.Columns.Add(column);
// Create second column.
column = new DataColumn();
column.DataType= System.Type.GetType("System.String");
column.ColumnName = "ChildItem";
column.AutoIncrement = false;
column.Caption = "ChildItem";
column.ReadOnly = false;
column.Unique = false;
table.Columns.Add(column);
// Create third column.
column = new DataColumn();
column.DataType= System.Type.GetType("System.Int32");
column.ColumnName = "ParentID";
column.AutoIncrement = false;
column.Caption = "ParentID";
column.ReadOnly = false;
column.Unique = false;
table.Columns.Add(column);
dataSet.Tables.Add(table);
// Create three sets of DataRow objects,
// five rows each, and add to DataTable.
for(int i = 0; i <= 4; i ++)
{
row = table.NewRow();
row["childID"] = i;
row["ChildItem"] = "Item " + i;
row["ParentID"] = 0 ;
table.Rows.Add(row);
}
for(int i = 0; i <= 4; i ++)
{
row = table.NewRow();
row["childID"] = i + 5;
row["ChildItem"] = "Item " + i;
row["ParentID"] = 1 ;
table.Rows.Add(row);
}
for(int i = 0; i <= 4; i ++)
{
row = table.NewRow();
row["childID"] = i + 10;
row["ChildItem"] = "Item " + i;
row["ParentID"] = 2 ;
table.Rows.Add(row);
}
}
private void MakeDataRelation()
{
// DataRelation requires two DataColumn
// (parent and child) and a name.
DataColumn parentColumn =
dataSet.Tables["ParentTable"].Columns["id"];
DataColumn childColumn =
dataSet.Tables["ChildTable"].Columns["ParentID"];
DataRelation relation = new
DataRelation("parent2Child", parentColumn, childColumn);
dataSet.Tables["ChildTable"].ParentRelations.Add(relation);
}
private void BindToDataGrid()
{
// Instruct the DataGrid to bind to the DataSet, with the
// ParentTable as the topmost DataTable.
dataGrid1.SetDataBinding(dataSet,"ParentTable");
}
更深入的：https://msdn.microsoft.com/zh-cn/library/system.data.datatable(v=vs.110).aspx#
二、访问数据库的两种方式：
1.客户端每次访问数据库时，都会发送请求
2.将信息存储到DataSet中，对DataSet进行访问，断开与数据库的连接时发送请求。该方法可以避免频繁操作数据库，但是可能会出现数据库不同步的问题
三、c#连接mysql
1.下载MySql.Data.dll，然后在项目中添加该引用，并且使用MySql.Data.MySqlClient这个命名空间
2.
using MySql.Data.MySqlClient;
using System;
using System.Data;
using System.Text;
public class MySqlUtility {
private static MySqlConnection mySqlConnection;
private static DataSet dataSet;
private static StringBuilder stringBuilder;
/// <summary>
/// 对于host，如果是本地的话，则写localhost
/// 如果是局域网，则写本机的局域网IP
/// </summary>
/// <param name="host"></param>
/// <param name="port"></param>
/// <param name="database"></param>
/// <param name="id"></param>
/// <param name="password"></param>
public static void Open(string host = "localhost", string port = "3306", string database = "test", string id = "hong", string password = "hong")
{
try
{
string s = string.Format("Server = {0};port = {1};Database = {2};User ID = {3};Password = {4};", host, port, database, id, password);
mySqlConnection = new MySqlConnection(s);
mySqlConnection.Open();
dataSet = new DataSet();
}
catch(Exception e)
{
throw new Exception("服务器连接失败，请重新检查是否打开MySql服务。" + e.Message.ToString());
}
}
public static void Close()
{
if (mySqlConnection != null)
{
mySqlConnection.Close();
mySqlConnection = null;
dataSet = null;
stringBuilder = null;
}
}
private static void ExecuteNotReturnDataSet(string statement)
{
//Debug.Log(statement);
MySqlCommand mySqlCommand = new MySqlCommand(statement, mySqlConnection);
mySqlCommand.ExecuteNonQuery();
}
private static DataSet ExecuteReturnDataSet(string statement)
{
//Debug.Log(statement);
MySqlDataAdapter mySqlDataAdapter = new MySqlDataAdapter(statement, mySqlConnection);
mySqlDataAdapter.Fill(dataSet);
return dataSet;
}
/// <summary>
/// 插入一行中的全部数据，对于值，统一转化为字符串进行处理
/// INSERT INTO 表名称 VALUES (值1, 值2,....)
/// </summary>
/// <param name="tableName"></param>
/// <param name="values"></param>
public static void Insert(string tableName, string[] values)
{
stringBuilder = new StringBuilder("insert into " + tableName + " values (" + "'" + values[0] + "'");
for (int i = 1; i < values.Length; i++)
{
stringBuilder.Append("," + "'" + values[i] + "'");
}
stringBuilder.Append(")");
ExecuteNotReturnDataSet(stringBuilder.ToString());
}
/// <summary>
/// 插入一行中的部分数据
/// INSERT INTO 表名称 (列1, 列2,...) VALUES (值1, 值2,....)
/// </summary>
/// <param name="tableName"></param>
/// <param name="columnNames"></param>
/// <param name="values"></param>
public static void Insert(string tableName, string[] columnNames, string[] values)
{
stringBuilder = new StringBuilder("insert into " + tableName + " (" + columnNames[0]);
for (int i = 1; i < columnNames.Length; i++)
{
stringBuilder.Append("," + columnNames[i]);
}
stringBuilder.Append(") values (" + "'" + values[0] +"'");
for (int i = 1; i < values.Length; i++)
{
stringBuilder.Append("," + "'" + values[i] + "'");
}
stringBuilder.Append(")");
ExecuteNotReturnDataSet(stringBuilder.ToString());
}
/// <summary>
/// SELECT * FROM 表名称
/// </summary>
/// <param name="tableName"></param>
/// <returns></returns>
public static DataSet Select(string tableName)
{
stringBuilder = new StringBuilder("select * from " + tableName);
return ExecuteReturnDataSet(stringBuilder.ToString());
}
/// <summary>
/// SELECT 列名称 FROM 表名称
/// </summary>
/// <param name="tableName"></param>
/// <param name="columnNames"></param>
/// <returns></returns>
public static DataSet Select(string tableName, string[] columnNames)
{
stringBuilder = new StringBuilder("select " + columnNames[0]);
for (int i = 1; i < columnNames.Length; i++)
{
stringBuilder.Append("," + columnNames[i]);
}
stringBuilder.Append(" from " + tableName);
return ExecuteReturnDataSet(stringBuilder.ToString());
}
/// <summary>
/// SELECT 列名称 FROM 表名称 WHERE 列 运算符 值
/// </summary>
/// <param name="tableName"></param>
/// <param name="columnNames"></param>
/// <param name="cols"></param>
/// <param name="operations"></param>
/// <param name="values"></param>
/// <returns></returns>
public static DataSet Select(string tableName, string[] columnNames, string[] cols, string[] operations, string[] values)
{
stringBuilder = new StringBuilder("select " + columnNames[0]);
for (int i = 1; i < columnNames.Length; i++)
{
stringBuilder.Append("," + columnNames[i]);
}
stringBuilder.Append(" from " + tableName + " where " + cols[0] + operations[0] + "'" + values[0] + "'");
for (int i = 1; i < cols.Length; i++)
{
stringBuilder.Append(" and " + cols[i] + operations[i] + "'" + values[i] + "'");
}
return ExecuteReturnDataSet(stringBuilder.ToString());
}
/// <summary>
/// UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值
/// </summary>
/// <param name="tableName"></param>
/// <param name="columnNames"></param>
/// <param name="newValues"></param>
/// <param name="cols"></param>
/// <param name="oldValues"></param>
public static void Update(string tableName, string[] columnNames, string[] newValues, string[] cols, string[] oldValues)
{
stringBuilder = new StringBuilder("update " + tableName + " set " + columnNames[0] + "='" + newValues[0] +"'");
for (int i = 1; i < columnNames.Length; i++)
{
stringBuilder.Append("," + columnNames[i] + "='" + newValues[i] + "'");
}
stringBuilder.Append(" where " + cols[0] + " ='" + oldValues[0] + "'");
for (int i = 1; i < cols.Length; i++)
{
stringBuilder.Append(" and " + cols[i] + "='" + oldValues[i] + "'");
}
ExecuteNotReturnDataSet(stringBuilder.ToString());
}
/// <summary>
/// DELETE FROM 表名称 WHERE 列名称 = 值
/// </summary>
/// <param name="tableName"></param>
/// <param name="columnNames"></param>
/// <param name="values"></param>
public static void Delete(string tableName, string[] columnNames, string[] values)
{
stringBuilder = new StringBuilder("delete from " + tableName + " where " + columnNames[0] + "='" + values[0] + "'");
for (int i = 1; i < columnNames.Length; i++)
{
stringBuilder.Append(" or " + columnNames[i] + "='" + values[i] + "'");
}
ExecuteNotReturnDataSet(stringBuilder.ToString());
}
}
四、unity连接mysql
1.在Assets下建一个文件夹，命名为Plugins，然后放入这些dll：http://pan.baidu.com/s/1i56gDfB
2.复制上面的脚本
3.
using UnityEngine;
using System.Collections;
using System.Data;
//若出现ReflectionTypeLoadException错误，需要将Player Settings中的
//Api Compatibility Level改为.Net2.0
public class NewBehaviourScript : MonoBehaviour {
void Start ()
{
MySqlUtility.Open();
DataSet ds = MySqlUtility.Select("human", new string[] { "*" }, new string[] { "age" }, new string[] { "=" }, new string[] { "222" });
PrintLog(ds);
MySqlUtility.Close();
}
public void PrintLog(DataSet ds)
{
if (ds == null)
{
Debug.Log("DebugLog-------------DataSet is null");
return;
};
DataTable dt = ds.Tables[0];
if (dt == null)
{
Debug.Log("DebugLog-------------DataTable is null");
}
foreach (DataRow row in dt.Rows)
{
foreach (DataColumn column in dt.Columns)
{
Debug.Log(row[column]);
}
}
}
}