数据库系统设计初步

C#2005实现的简单解题系统，数据库课程设计准备知识。实现数据绑定，记录定位，更新数据，查询数据等功能。其他功能可以在此基础上增加。

方便起见使用ACCESS建立数据库；建立两张表： questions(序号，内容)，序号：自动编号 answers(id，学号，姓名，问题ID，答案，提交时间)，id：自动编号，问题ID参照questions(序号)。

功能代码为

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Data.OleDb;



namespace testIt

{

    public partial class frmTest : Form

    {

        public frmTest()

        {

            InitializeComponent();

        }



        private OleDbConnection cnn;

        private OleDbDataAdapter da;        

        private DataSet ds;

        private OleDbCommand cmd;    

        private BindingManagerBase bm;

        private OleDbCommandBuilder cb;



        private void bm_PositionChanged(object sender, EventArgs e)

        {

            txtPosition.Text = "Rec " + (bm.Position + 1) + " of " + bm.Count;

        }



        private void frmTest_Load(object sender, EventArgs e)

        {

            cnn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + "d://test//tm.mdb");

            cnn.Open();

            da = new OleDbDataAdapter("select 序号,内容 from questions", cnn);

            ds = new DataSet();

            da.Fill(ds, "questions");

            

            OleDbDataAdapter daAnswer = new OleDbDataAdapter("select 问题ID from answers", cnn);

            daAnswer.Fill(ds, "answers");

            cboContests.DataSource = ds.Tables["questions"];

            cboContests.DisplayMember = "内容";

            cboContests.ValueMember = "序号";

            cboContests.DataBindings.Add("SelectedValue", ds, "answers.问题ID");



            dgvContents.DataSource = ds;

            dgvContents.DataMember = "questions";



            bm = this.BindingContext[ds,"questions"];

            bm.CurrentChanged += new EventHandler(bm_PositionChanged);

            txtPosition.Text = "Rec " + (bm.Position + 1) + " of " + bm.Count;



            rtxtContents.DataBindings.Add(new Binding("text", ds, "questions.内容"));



            cmd = new OleDbCommand();

            cmd.Connection = cnn;



            cb = new OleDbCommandBuilder(da);

        }



        private void btnNext_Click(object sender, EventArgs e)

        {

            bm.Position++;  

        }



        private void btnLast_Click(object sender, EventArgs e)

        {

            bm.Position = bm.Count;

        }



        private void btnPrevious_Click(object sender, EventArgs e)

        {

            bm.Position--;            

        }



        private void btnFirst_Click(object sender, EventArgs e)

        {

            bm.Position = 0;

        }



        private void btnCommit_Click(object sender, EventArgs e)

        {

            cmd.CommandType = CommandType.Text;

            OleDbCommand cmdTemp=new OleDbCommand("select 序号 from questions where 内容='" + rtxtContents.Text + "'",cnn);

            OleDbDataReader dr=cmdTemp.ExecuteReader();

            

            dr.Read();

            string id=dr.GetValue(0).ToString();



            string strSql = "insert into answers(学号,姓名,问题ID,答案,提交时间) values('" + txtNo.Text  + "','" + txtName.Text  + "'," + 

                                                           id + ",'" + rtxtAnswer.Text + "','" + DateTime.Now + "')";  



            cmd.CommandText = strSql;

            int cnt=cmd.ExecuteNonQuery();

            if (cnt > 0)

            {

                MessageBox.Show("提交成功！");

            }            

        }



        private void btnInsert_Click(object sender, EventArgs e)

        {

            bm.AddNew();

        }



        private void btnSave_Click(object sender, EventArgs e)

        {

            bm.EndCurrentEdit();

            da.Update(ds, "questions");

            ds.AcceptChanges();

        }



        private void btnDelete_Click(object sender, EventArgs e)

        {

            bm.RemoveAt(bm.Position);

            da.Update(ds, "questions");

        }



        private void btnCancel_Click(object sender, EventArgs e)

        {

            bm.CancelCurrentEdit();

        }



        private void btnLocate_Click(object sender, EventArgs e)

        {

            int i;

            for (i = 0; i < bm.Count; i++)

            {

                bm.Position = i;

                DataRowView curRow = (DataRowView)bm.Current;

                if (curRow["内容"].ToString() == txtInput.Text) break;

            }



            if (i >= bm.Count) MessageBox.Show("找不到!");

        }

    }

}

//连接MS  Sql Server数据库，要修改连接串如下(test为数据库名,登录名与登录密码都是sa) 。

using System.Data.OleDb; 

OleDbConnection cnn = new OleDbConnection("Provider=SqlOledb.1;Server=(local);database=test;uid=sa;pwd=sa"); 

cnn.Open(); 

//或 

using System.Data.SqlClient; 

SqlConnection cnn = new SqlConnection("Server=(local);database=test;uid=sa;pwd=sa"); 

cnn.Open(); 

//界面设计代码为
namespace testIt

{

    partial class frmTest

    {

        /// <summary>

        /// 必需的设计器变量。

        /// </summary>

        private System.ComponentModel.IContainer components = null;



        /// <summary>

        /// 清理所有正在使用的资源。

        /// </summary>

        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>

        protected override void Dispose(bool disposing)

        {

            if (disposing && (components != null))

            {

                components.Dispose();

            }

            base.Dispose(disposing);

        }



        #region Windows 窗体设计器生成的代码



        /// <summary>

        /// 设计器支持所需的方法 - 不要

        /// 使用代码编辑器修改此方法的内容。

        /// </summary>

        private void InitializeComponent()

        {

            this.label1 = new System.Windows.Forms.Label();

            this.label2 = new System.Windows.Forms.Label();

            this.txtNo = new System.Windows.Forms.TextBox();

            this.txtName = new System.Windows.Forms.TextBox();

            this.btnCommit = new System.Windows.Forms.Button();

            this.lblContents = new System.Windows.Forms.Label();

            this.dgvContents = new System.Windows.Forms.DataGridView();

            this.rtxtContents = new System.Windows.Forms.RichTextBox();

            this.btnNext = new System.Windows.Forms.Button();

            this.btnLast = new System.Windows.Forms.Button();

            this.btnPrevious = new System.Windows.Forms.Button();

            this.btnFirst = new System.Windows.Forms.Button();

            this.txtPosition = new System.Windows.Forms.TextBox();

            this.rtxtAnswer = new System.Windows.Forms.RichTextBox();

            this.label3 = new System.Windows.Forms.Label();

            this.label4 = new System.Windows.Forms.Label();

            this.button1 = new System.Windows.Forms.Button();

            this.btnDelete = new System.Windows.Forms.Button();

            this.btnInsert = new System.Windows.Forms.Button();

            this.btnLocate = new System.Windows.Forms.Button();

            this.txtInput = new System.Windows.Forms.TextBox();

            this.btnSave = new System.Windows.Forms.Button();

            this.btnCancel = new System.Windows.Forms.Button();

            this.cboContests = new System.Windows.Forms.ComboBox();

            ((System.ComponentModel.ISupportInitialize)(this.dgvContents)).BeginInit();

            this.SuspendLayout();

            // 

            // label1

            // 

            this.label1.AutoSize = true;

            this.label1.Location = new System.Drawing.Point(3, 24);

            this.label1.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);

            this.label1.Name = "label1";

            this.label1.Size = new System.Drawing.Size(32, 16);

            this.label1.TabIndex = 0;

            this.label1.Text = "Sno";

            // 

            // label2

            // 

            this.label2.AutoSize = true;

            this.label2.Location = new System.Drawing.Point(194, 24);

            this.label2.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);

            this.label2.Name = "label2";

            this.label2.Size = new System.Drawing.Size(48, 16);

            this.label2.TabIndex = 1;

            this.label2.Text = "Sname";

            // 

            // txtNo

            // 

            this.txtNo.Location = new System.Drawing.Point(40, 14);

            this.txtNo.Margin = new System.Windows.Forms.Padding(4);

            this.txtNo.MaxLength = 8;

            this.txtNo.Name = "txtNo";

            this.txtNo.Size = new System.Drawing.Size(132, 26);

            this.txtNo.TabIndex = 2;

            // 

            // txtName

            // 

            this.txtName.Location = new System.Drawing.Point(242, 14);

            this.txtName.Margin = new System.Windows.Forms.Padding(4);

            this.txtName.Name = "txtName";

            this.txtName.Size = new System.Drawing.Size(132, 26);

            this.txtName.TabIndex = 3;

            // 

            // btnCommit

            // 

            this.btnCommit.Location = new System.Drawing.Point(394, 299);

            this.btnCommit.Name = "btnCommit";

            this.btnCommit.Size = new System.Drawing.Size(75, 32);

            this.btnCommit.TabIndex = 4;

            this.btnCommit.Text = "Commit";

            this.btnCommit.UseVisualStyleBackColor = true;

            this.btnCommit.Click += new System.EventHandler(this.btnCommit_Click);

            // 

            // lblContents

            // 

            this.lblContents.AutoSize = true;

            this.lblContents.Location = new System.Drawing.Point(96, 98);

            this.lblContents.Name = "lblContents";

            this.lblContents.Size = new System.Drawing.Size(0, 16);

            this.lblContents.TabIndex = 6;

            // 

            // dgvContents

            // 

            this.dgvContents.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;

            this.dgvContents.Location = new System.Drawing.Point(394, 12);

            this.dgvContents.Name = "dgvContents";

            this.dgvContents.RowTemplate.Height = 23;

            this.dgvContents.Size = new System.Drawing.Size(245, 254);

            this.dgvContents.TabIndex = 7;

            // 

            // rtxtContents

            // 

            this.rtxtContents.Location = new System.Drawing.Point(12, 77);

            this.rtxtContents.Name = "rtxtContents";

            this.rtxtContents.Size = new System.Drawing.Size(171, 254);

            this.rtxtContents.TabIndex = 8;

            this.rtxtContents.Text = "";

            // 

            // btnNext

            // 

            this.btnNext.Location = new System.Drawing.Point(216, 337);

            this.btnNext.Name = "btnNext";

            this.btnNext.Size = new System.Drawing.Size(83, 32);

            this.btnNext.TabIndex = 10;

            this.btnNext.Text = "Next";

            this.btnNext.UseVisualStyleBackColor = true;

            this.btnNext.Click += new System.EventHandler(this.btnNext_Click);

            // 

            // btnLast

            // 

            this.btnLast.Location = new System.Drawing.Point(305, 337);

            this.btnLast.Name = "btnLast";

            this.btnLast.Size = new System.Drawing.Size(83, 32);

            this.btnLast.TabIndex = 11;

            this.btnLast.Text = "Last";

            this.btnLast.UseVisualStyleBackColor = true;

            this.btnLast.Click += new System.EventHandler(this.btnLast_Click);

            // 

            // btnPrevious

            // 

            this.btnPrevious.Location = new System.Drawing.Point(394, 337);

            this.btnPrevious.Name = "btnPrevious";

            this.btnPrevious.Size = new System.Drawing.Size(83, 32);

            this.btnPrevious.TabIndex = 12;

            this.btnPrevious.Text = "Previous";

            this.btnPrevious.UseVisualStyleBackColor = true;

            this.btnPrevious.Click += new System.EventHandler(this.btnPrevious_Click);

            // 

            // btnFirst

            // 

            this.btnFirst.Location = new System.Drawing.Point(483, 337);

            this.btnFirst.Name = "btnFirst";

            this.btnFirst.Size = new System.Drawing.Size(83, 32);

            this.btnFirst.TabIndex = 13;

            this.btnFirst.Text = "First";

            this.btnFirst.UseVisualStyleBackColor = true;

            this.btnFirst.Click += new System.EventHandler(this.btnFirst_Click);

            // 

            // txtPosition

            // 

            this.txtPosition.Location = new System.Drawing.Point(12, 343);

            this.txtPosition.Name = "txtPosition";

            this.txtPosition.Size = new System.Drawing.Size(198, 26);

            this.txtPosition.TabIndex = 14;

            // 

            // rtxtAnswer

            // 

            this.rtxtAnswer.Location = new System.Drawing.Point(193, 77);

            this.rtxtAnswer.Name = "rtxtAnswer";

            this.rtxtAnswer.Size = new System.Drawing.Size(181, 254);

            this.rtxtAnswer.TabIndex = 15;

            this.rtxtAnswer.Text = "";

            // 

            // label3

            // 

            this.label3.AutoSize = true;

            this.label3.Location = new System.Drawing.Point(2, 58);

            this.label3.Name = "label3";

            this.label3.Size = new System.Drawing.Size(72, 16);

            this.label3.TabIndex = 16;

            this.label3.Text = "Question";

            // 

            // label4

            // 

            this.label4.AutoSize = true;

            this.label4.Location = new System.Drawing.Point(190, 58);

            this.label4.Name = "label4";

            this.label4.Size = new System.Drawing.Size(96, 16);

            this.label4.TabIndex = 17;

            this.label4.Text = "Your Answer";

            // 

            // button1

            // 

            this.button1.Location = new System.Drawing.Point(483, 299);

            this.button1.Name = "button1";

            this.button1.Size = new System.Drawing.Size(75, 32);

            this.button1.TabIndex = 18;

            this.button1.Text = "Update";

            this.button1.UseVisualStyleBackColor = true;

            // 

            // btnDelete

            // 

            this.btnDelete.Location = new System.Drawing.Point(564, 299);

            this.btnDelete.Name = "btnDelete";

            this.btnDelete.Size = new System.Drawing.Size(75, 32);

            this.btnDelete.TabIndex = 19;

            this.btnDelete.Text = "Delete";

            this.btnDelete.UseVisualStyleBackColor = true;

            this.btnDelete.Click += new System.EventHandler(this.btnDelete_Click);

            // 

            // btnInsert

            // 

            this.btnInsert.Location = new System.Drawing.Point(645, 299);

            this.btnInsert.Name = "btnInsert";

            this.btnInsert.Size = new System.Drawing.Size(75, 32);

            this.btnInsert.TabIndex = 20;

            this.btnInsert.Text = "Insert";

            this.btnInsert.UseVisualStyleBackColor = true;

            this.btnInsert.Click += new System.EventHandler(this.btnInsert_Click);

            // 

            // btnLocate

            // 

            this.btnLocate.Location = new System.Drawing.Point(726, 299);

            this.btnLocate.Name = "btnLocate";

            this.btnLocate.Size = new System.Drawing.Size(75, 32);

            this.btnLocate.TabIndex = 21;

            this.btnLocate.Text = "Locate";

            this.btnLocate.UseVisualStyleBackColor = true;

            this.btnLocate.Click += new System.EventHandler(this.btnLocate_Click);

            // 

            // txtInput

            // 

            this.txtInput.Location = new System.Drawing.Point(619, 345);

            this.txtInput.Name = "txtInput";

            this.txtInput.Size = new System.Drawing.Size(127, 26);

            this.txtInput.TabIndex = 22;

            // 

            // btnSave

            // 

            this.btnSave.Location = new System.Drawing.Point(807, 299);

            this.btnSave.Name = "btnSave";

            this.btnSave.Size = new System.Drawing.Size(75, 32);

            this.btnSave.TabIndex = 23;

            this.btnSave.Text = "Save";

            this.btnSave.UseVisualStyleBackColor = true;

            this.btnSave.Click += new System.EventHandler(this.btnSave_Click);

            // 

            // btnCancel

            // 

            this.btnCancel.Location = new System.Drawing.Point(807, 337);

            this.btnCancel.Name = "btnCancel";

            this.btnCancel.Size = new System.Drawing.Size(75, 32);

            this.btnCancel.TabIndex = 24;

            this.btnCancel.Text = "Cancel";

            this.btnCancel.UseVisualStyleBackColor = true;

            this.btnCancel.Click += new System.EventHandler(this.btnCancel_Click);

            // 

            // cboContests

            // 

            this.cboContests.FormattingEnabled = true;

            this.cboContests.Location = new System.Drawing.Point(690, 12);

            this.cboContests.Name = "cboContests";

            this.cboContests.Size = new System.Drawing.Size(121, 24);

            this.cboContests.TabIndex = 25;

            // 

            // frmTest

            // 

            this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 16F);

            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;

            this.ClientSize = new System.Drawing.Size(894, 388);

            this.Controls.Add(this.cboContests);

            this.Controls.Add(this.btnCancel);

            this.Controls.Add(this.btnSave);

            this.Controls.Add(this.txtInput);

            this.Controls.Add(this.btnLocate);

            this.Controls.Add(this.btnInsert);

            this.Controls.Add(this.btnDelete);

            this.Controls.Add(this.button1);

            this.Controls.Add(this.label4);

            this.Controls.Add(this.label3);

            this.Controls.Add(this.rtxtAnswer);

            this.Controls.Add(this.txtPosition);

            this.Controls.Add(this.btnFirst);

            this.Controls.Add(this.btnPrevious);

            this.Controls.Add(this.btnLast);

            this.Controls.Add(this.btnNext);

            this.Controls.Add(this.rtxtContents);

            this.Controls.Add(this.dgvContents);

            this.Controls.Add(this.lblContents);

            this.Controls.Add(this.btnCommit);

            this.Controls.Add(this.txtName);

            this.Controls.Add(this.txtNo);

            this.Controls.Add(this.label2);

            this.Controls.Add(this.label1);

            this.Font = new System.Drawing.Font("宋体", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));

            this.Margin = new System.Windows.Forms.Padding(4);

            this.Name = "frmTest";

            this.Text = "Database&C#";

            this.Load += new System.EventHandler(this.frmTest_Load);

            ((System.ComponentModel.ISupportInitialize)(this.dgvContents)).EndInit();

            this.ResumeLayout(false);

            this.PerformLayout();



        }



        #endregion



        private System.Windows.Forms.Label label1;

        private System.Windows.Forms.Label label2;

        private System.Windows.Forms.TextBox txtNo;

        private System.Windows.Forms.TextBox txtName;

        private System.Windows.Forms.Button btnCommit;

        private System.Windows.Forms.Label lblContents;

        private System.Windows.Forms.DataGridView dgvContents;

        private System.Windows.Forms.RichTextBox rtxtContents;

        private System.Windows.Forms.Button btnNext;

        private System.Windows.Forms.Button btnLast;

        private System.Windows.Forms.Button btnPrevious;

        private System.Windows.Forms.Button btnFirst;

        private System.Windows.Forms.TextBox txtPosition;

        private System.Windows.Forms.RichTextBox rtxtAnswer;

        private System.Windows.Forms.Label label3;

        private System.Windows.Forms.Label label4;

        private System.Windows.Forms.Button button1;

        private System.Windows.Forms.Button btnDelete;

        private System.Windows.Forms.Button btnInsert;

        private System.Windows.Forms.Button btnLocate;

        private System.Windows.Forms.TextBox txtInput;

        private System.Windows.Forms.Button btnSave;

        private System.Windows.Forms.Button btnCancel;

        private System.Windows.Forms.ComboBox cboContests;

    }

}