c图书管理系统源代码

1、1.登陆界面 主要代码: pub Iic partial class Log inForm : Form( pub Iic static string uacc; pub Iic static string upsw; pub Iic static string uname; pub Iic static string usex; pub Iic static string upart; pub Iic static string ur ight; pub Iic LoginFormO InitializeComponent(); private void Ioginbtn_CIick(obj

2、ect sender, EventArgs e) if (this, useracctxt. Text. Tr im() =” ) try string sql; sql = select * from tb_user where uacc=， + this, useracctxt Text + and upsvr= + thispswtxt .Text + ; OleDbDataReader dr = DBHeIp. 01 eReader(sqI); dr. Read (); if (dr.HasRows) uacc = thisuseracctxt .Text; upsw = thisps

3、wtxt .Text; uname = dr unameT oStringO; usex = drusexToStringO ; upart = dr apart.ToStr ing(); ur ight = drur ightJ. ToStr ing(); Main Form af = nev/ Main Form (th is); this. Hide (); this useracctxt Clear(); this, psvrtxt. Clear (); af. Show (); ) else MessageBox. ShowCRK号或密码错误!提示！ “); t his user a

4、cct xt Clear (); this, pswtxt. Clear (); this, useracctxt Focus(); 1 catch (Exception) MessageBox. Show库无法连接！ ” “警告！ ”)； 1 1 private void canceIbtn_CIick(object sender. EventArgs e) Appl icat ion. Exi t (); 1 private void LoginForm_Closing(object sender, FormClosingEventArgs e) Appl icat ion. Exit (

5、); 1 2主界面(图较小，自己可以拉大点) 主要代码就不写了，很简单。 3.权限设置 主要代码： public partial class RightSet : Form pub I ic RightSet () Init iali zeComponent(); ) private void RightSet_Load(object sender, EventArgs e) this. rightbox.SeIectedIndex = 0; /thi s. treer ight. ExpandA 11(); FillO; ) private void okbtn_CIick(object s

6、ender. EventArgs e) if (thistxtnum. Text = str ing.Empty) MessageBox.Show(n请输入最大借阅图书数量！ “提示！ ”)； return; if (thistxtday. Text = str ing.Empty) MessageBox.ShowC请输入最大借阅图书时间!”提示！ “)； return; if (thistxtcostText = string.Empty) 1 MessageBox.ShowC*请输入借书押金金颔！”提示！ ”)； return; if (this, txtfine. Text = str

7、ing.Empty) MessageBoXeShowC请输入媲期罚飲金额！”提示！ “)； return; if (this. txttim.Text = str ing Empty) MessageBox.ShowC请输入图书遗失罚款倍数！“，“提示！ ”)； return; ) ArrayLi st arr = new ArrayLi st(); foreach (TreeNode nodes in thistreeright.Nodes) i f (nodes. Checked) arr. Add(1); else arr. Add(O); foreach(TreeNode node i

8、n nodes .Nodes) if (node. Checked) arr. Add (I); 1 else arrAdd(“0“)； 1 str i ng a二new str i ng11; for (int i = 0; i arr.Count; i+) if (arr i. ToStr ing(). Tr im() = T ) ai = yes; ) else ai = no; 1 str i ng sql = str i ng.Empty; sql += select * from tb_right where ur ight=* + thisrightboxText + DataT

9、able dt = DBHeIp. ExeOI eCommand(sqI); bool b = false; while (dt. Rows. Count != 0) b = true; break; 1 str ing sql1; if (b) sql 1 =update tb_ right set ; sql 1 += “maxbook二 + thistxtnum.Text + sql 1 += “maxdate二 + this, txtday. Text + sql 1 += urcost=, + this t xtcost .Text + sql 1 += Mrfine=,M + th

10、is.txtfine. Text + *, ; sql 1 this, txttim. Text + sql 1 += Hrbn=,w + a0 + /； sql 1 += Mrum=- + a1 + M,M; sql 1 += Mrrm=,w + a 2 + M,; sql 1 += Mrborm=,M + a 3 + sql 1 += Mris=- + a 4 + sql 1 ”rbis=” 4 a 5 + -M; sql 1 += Mruis=*- 4 a 6 + *, ; sql 1 += Mrboris=,H + a 7 + Mw; sql 1 += Mrblp=*- 4 a 8 +

11、 -M; sql 1 += Mrbl=- + a 9 + :“； sql 1 += “rip 十 + a 10 + ； sql 1 += where ur ight二” + thisrightbox.Text + ) else sql1 = insert into tb_r ight(ur ight, maxbook, maxdate. rcost, rfine. rt im. rbm. rum,rrm, rborm. ris, rbis,ruis,rboris,rblp ,rbl, r Ip); sql 1 += vaIues( + this.r ightbox.Text + “ ， “ +

12、 this.txtnum.Text + M + this, txtday. Text + + this, txtcost. Text + 八，” + this, txtf ine. Text + this.txttim. Text + a0 + M, ,u + al +a 2 + a 3令：+ a 4 + :* a5 + n, ,H + a6 + / + a刀 + ,M + a8 + ,M + a9 + ,M + a(10 + H,)w; DataTable dt1 = DBHeIp.ExeOI eCommand(sq11); FillO; 1 private void Fi I I () s

13、tr ing sql; sql = “selec t rid as ID 号.ur igh t as 用户身份.maxbook as 礙大借书数量,maxdate as it 大倍阅时间,rcost as押金，rf ine as趨期罚率.rtim as遗失踣準，rbm as图书管理，rum as用户管 理.rrm as权限管理,rborm as借阅管理,ris as信息查询,rbis as图书信息查询,ruis as用户信息查 询,rbor is as借阅历史查询,rblp as图书挂失处理，rbl as图书挂失,r Ip as挂失处理from tb_r ight; DataTable dt

14、= DBHeIp.ExeOI eCommand(sqI); th i s. dataGr i dV i ev/1. DataSource = dt; 1 private void cell_click(object sender, DataGridViewCeI iEventArgs e) this, rightbox. Text = this. dataGridViev/1 1t this. dataGr idVi ev/1. CurrentCe 11. Row Index. Value. ToStr ing(). Tr im(); this, txtnum. Text = this.dat

15、aGridView12, this. dataGr idVi ev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr im(); this. txtday. Text = this.dataGridView13, this. dataGr idVi ev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr imO ； this. txtcost. Text = thi s.dataGr idView14, this. dataGr idVi ev/1. CurrentCe 11. Ro

16、w Index. Value. ToStr i ng (). Tr im(); this, txtf ine. Text = this. dataGr idViev/1 5, this. dataGr idViewl. CurrentCeI I. Row Index. Value. ToStr ing(). T r i m(); this. txttim. Text = this.dataGridView16, this. dataGr idViev/1 CurrentCe 11 Row Index. Value. ToStr i ng (). T r i m (); ArrayList li

17、st 二 new ArrayList(); str i ng sql = select from tb_r ight where ur ight=* * + thisrightbox.Text + ; DataTable dt = DBHeIp. ExeOI eCommand(sqI); if (dt.Rows. Count != 0) for (int i = 0; i 11; i+) I ist. Add (dt. Rows0 7+ i. ToStr ing (); ArrayLi st arr = new ArrayLi st(); foreach (TreeNode nodes in

18、thistreerightNodes) arr.Add (nodes); foreach (TreeNode node in nodes .Nodes) arr. Add (node); 1 for (int i =0; i Iist.Count; i+) if (Iisti.ToString() = yes) (TreeNode)arri). Checked = true; 1 else (TreeNode)arri). Checked = false; 1 ) ) 1 4.权限修改 主要代码: ) public partial class UserRight : Form publ ic

19、UserRight () Initiali zeComponent(); ) private void btncancel_CIick(object sender. EventArgs e) this. Close(); ) private void UserRight_Load(object sender, EventArgs e) this .checkbox .Selected Index = 0; thispartboxSelected Index = 0; ) private void Fi I I () (this .checkbox .Text = if MessageBox.S

20、how（请逸择要使用的查询字R! M提示！ “）； return; if (this, partbox. Text = ”) MessageBox.ShowC*请选择用户所在的部门！ ”，提示! ”)； return; 1 str i ng sql = str i ng.Empty; sql += select uid as ID号，uacc as . uname as , usex as 性别，upart as 部门.utelphone as 移动,uphone as 固定,udate as 注册日期,ur ight as 权限 from tb_userM; if (this.checktx

21、t. Text !=*) str i ng c = this.checkboxSelectedlndexToString(); sw i tch (c) case M0H:/用户 if (thischecktxt .Text != string.Empty) sql +二 “where uacc I ike % + th i s.checktxt.Text + 和； break; case T1:/用户 if (thischecktxtText 匸 string.Empty) sql += where uname I ike + this.checktxt.Text +; break; def

22、ault: break; 1 if (this, partbox. Selectedlndex. ToStr ing() != 0 ) sql += ” and upart=,u + this.partbox. Text + ; 1 1 else if (this.partbox. Selectedlndex.ToStr ing() != 0”) sql += “ where upart=， + thispartbox.Text + sql += “ order by uacc asc* ; DataTable dt = DBHeIp. ExeOI eCommand(sqI); th i s.

23、 dataGr i dV i ev/1. DataSource = dt; private void checkbtn_CIick(object sender, EventArgs e) FillO; 1 private void cell_click(object sender, DataGr idViewCeI IEventArgs e) this, txtuacc. Text = this. dataGr idViev/1 1, this. dataGr idVi ev/1. CurrentCe 11. Row Index. Value. ToStr ing(). T r i m ();

24、 this, txtname. Text = this. dataGr idViev/1 2, this. dataGr idViev/1 CurrentCe I I Row Index Value. ToStr i ng (). T r i m (); this, txtsex. Text = this.dataGridView13, this. dataGr idViev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). T r i m (); this. txtpart. Text = thi s.dataGr idView14, thi

25、s. dataGr idViev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr im(); this. txtteI Text = this.dataGridView15, this. dataGr idViev/1. CurrentCe I I. Row Index. Value. ToStr i ng (). T r i m (); this. txtphone. Text = this. dataGr idViev/1 6t this. dataGr idViev/1 CurrentCe 11 Row Index. Value.

26、 ToStr i ng (). Tr im(); this, txtdate. Text = this.dataGridViewl7, this. dataGr idViev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr im(); this, txtright. Text = this. dataGridViev/1 8, this. dataGr idViev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr im(); thistxtright .Enabled = tru

27、e; private void btnchange_CIick(object sender, EventArgs e) if (this, txtuacc. Text = ”) MessageBox.ShowC1执疔操作前，请先在下表逸择要修改的用户！ ”，”提示！ ”)； return; DialogResult res; ) res=MessageBox. Show(M您确定要修改该用户吗？ “，提示! “，MessageBoxButtons. YesNo); if (res = DialogResult. Yes) string sql = string.Empty; sql += up

28、date tb_user set ur ight=* M+thi s. txtright. Text*; sql += “ where uacc=* +thistxtuaccText*; DataTable dt = DBHeIp. ExeOI eCommand(sqI): MessageBox. ShowC*修改成功！恭喜！ “)； FillO; 1 5 添加图书信息 主要代码： pub Ii c partial class NewBook : Form pub I i c NewBook () InitializeComponent(); ) private void retbtn_CIi

29、ck(object sender, EventArgs e) this. Hide (); ) private void savebtn_CIick(object sender, EventArgs e) if (this, booknotxt. Text = MessageBox.ShowC1请输入图书的信息！ 提示！ ”)； return; if (this, booknametxt. Text =“) MessageBox.ShowC请输入图书的信息！提示！ ”); return; if (this, classtxt. Text =) MessageBox.ShowC1请输入图书的信息

30、！ ”，提示！ “); return; 1 if (this, isbntxt.Text = ”) MessageBox.ShowC1请楡入图书的信息！ ”，提示！ ”); return; if (this, bookcosttxt. Text =“) MessageBox.ShowC1请输入图书的信息！ ”，提示！ ”); return; 1 if (this.bookwr itertxt. Text = MessageBox.ShowC1请输入图书的信息！提示！ ”)； return; if (this, bookpubtxt. Text = ”) MessageBox.ShowC*请输入

31、图书的信息！提示！ ”)； return; 1 if (this, numtxt. Text = ”) MessageBox.ShowC*请输入图书的信息！ ”，提示！ ”)； return; if (this, notetxt. Text =) MessageBox.ShowC*请输入图书的信息！ -提示！ “）； return; ) /string pat3 = u4e00-u9fa5+$”；/全为汉字 /string pat4 =(u4e00-u9fa5*|A-Za-z+)$;/汉字或字母 /string pat5 =u4e00-u9fa5 (2,4$M;/两到四位汉字 string p

32、atl = (dH*) 9 dxX$M;/ 图书的 ISBN 号格式 X-XXXX-XXXX-X 或 X-XXX-XXXXX-X (X为数字，以图书实际ISBN号为准) string pat2 = +?卜9 0-9*$“ ；/ 正整数 string pat3 = (0|1-9 0-9*) (. 0-9 (2)?$M;/双耕度浮点数 bool ml = Programmatch(thisisbntxtText, patl); bool m2 = Programatch(this.numtxt.Text, pat2); bool m3 = Programmatch(thi s bookcosttx

33、t. Text, pat3); if (!m1) MessageBox. Show (” 图书的 ISBN号格式为X-XXXX-XXXX-X或X-XXX-XXXXX-X (X 为欽字.以 图书实际ISBN号为准)！ , 提示！ ”)； this, isbntxt.Text = “； return; if (!m2) MessageBox. Show (n图书购买教董应为大于0的整数！ “，”提示！ this, numtxt. Text = return; 1 if (!m3) MessageBox. Show(n 图书价格应为XX. XX元！ “提示! H); this, bookcosttx

34、t. Text = ”; return; 1 int num; num = Convert. To I nt32 (th i s. numtxt. Text); for (int i = 1, k = Convert.Tolnt32(this, booknotxt. Text): i = num; i+, k+) str ing sql; sql = insert into tb_book (bno,bname.be I ass,bisbn, boost, adder, adddate. bauthor, bpub bstate, bnote) “ + values(* + k. ToStri

35、ng() + , * + thisbooknametxtText + this.classtxt.Text + this, isbntxt. Text * , * + this, bookcosttxt. Text * Logi nForm un ame + DateT ime .Now T oStri ng() + ，八 + t his bookwritertxt Tex t + this, bookpubtxt. Text + 在库，八 + this, notetxt. Text + DataTable dt = DBHeIp. ExeOI eCommand(sqI): MessageBo

36、x. ShowC注册成功! “，“ 恭*! ”)； this. Hide (); 1 private void rebtn_CIick(object sender, EventArgs e) this, isbntxt. Clear (); ClearsO ; ) private void Clears0 th i s. booknametxt CI ear (); /th i s. i sbntxt. CI ear (); th i s. bookcosttxt. CI ear (); this, bookwritertxt. Clear (); th i s. bookpubtxt. CI

37、 ear (); this, notetxt. Clear (); this, numtxt. Clear (); 1 private void NewBook_Load(object sender, EventArgs e) / str ing sql; sql = select bno from tb_book order by bno asc; DataTable dt = DBHeIp. ExeOIeCommand(sqI); for (int i = 0. k = 10000001; i 1; i+t k+) for (int j = 0; j dt.Rows. Count; j+)

38、 if (dt. Rowsj 0. ToStr ing(). Tr im(). Equals(k. ToStr ing() k+； ) this, booknotxt. Items. Add (k. ToStr ing (); this.booknotxt. SeIectedIndex = 0; thi s.cI asstxt. SeIectedIndex = 0; / str i ng sql; sql = select top 1 bno from tb_book order by bno desc* ; DataTable dt = DBHeIp. ExeOI eCommand(sqI)

39、; int k; for (int i =0; i 1; i+) if (dt. Rows0 0. ToStr ing()=“) k = 10000001; 1 else k = Convert. Tolnt32(dt. Roy/s0 0. ToStr ing(); k+; 1 this, booknotxt. Items. Add (k. ToStr ing(); 1 thisbooknotxtSeIectedIndex = 0; this. classtxt. SeiectedIndex = 0; 1 private void findbtn_CIick(object sender, Ev

40、entArgs e) if (this, isbntxt.Text = ”) MessageBox.Show(n请输入图书的 ISBN号！ 提示！ w); return; str ing sql; sql = select * from tb_book where bisbn=,M + this isbntxtText + OleDbDataReader dr = DBHeIp.01 eReader(sqI); dr.Read 0; if (dr. HasRov/s) this booknametxt .Text = dr bnafne1 ToString()T r i m (); this,

41、 classtxt. Text = dr be lass. ToStr ing (). Tr im(); this. bookcosttxt. Text = dr boost. ToStr ing(). Tr im(); this, bookwritertxt. Text = dr bauthor. ToStr ing (). Tr im(); this, bookpubtxt. Text = dr*bpub. ToStr ing(). Tr im(); this, notetxt. Text = dr bnote*. ToStr ing(). Trim(); MessageBox.ShowC

42、1找到匹配图书信息.自动填充基本信息，请壊充余下信息！ “，“提示！ thisnumtxt .Enabled = true; else ClearsO ; MessageBox.ShowC未找到匹配图书信息！“提示！ “)； thisbooknotxt .Enabled = true; thisbooknametxt .Enabled = true; this, classtxt. Enabled = true; thisbookcosttxt .Enabled = true; thisbookwritertxtEnabled = true; thisbookpubtxt. Enabled =

43、 true; thisnumtxt .Enabled = true; thisnotetxt .Enabled = true; 1 1 1 6. 图书信息管理 3回区） 聞书基砒信息 固书信息丟 图书信息官理 主要代码： public partial class BookManage : Form pub I i c BookManage () Initiali zeComponent(); ) string bookisbn; private void BookManage_Load(object sender. EventArgs e) th i s.checkbox.SeIectedIn

44、dex = 0; thisclassbox .Selected Index = 0; private void checkbtn_CIick(object sender, EventArgs e) FillGridO; ) private void cell_click(object sender, DataGr idViewCeI IEventArgs e) Fill Info (); private void nobtn_CIick(object sender. EventArgs e) this. Close(); 1 private void okbtn_CIick(object se

45、nder, EventArgs e) if (this, nametxt. Text = string.Empty) MessageBox.ShowC1执疔操作前，请先逸择图书！“，“提示！ ”)； return; 1 /修改同ISBN图书信息 str ing sql2= str i ng.Empty; sql2 += update tb_book set bisb+ this isbntxtText + f bname=*u + this, nametxt. Text + bclass=*M + this.classtxt.Text + *,bcost=u + this, costtxt.

46、Text + , bauthor=, + this, v/r iter txt. Text + u 1. bpub= + this, pubtxt. Text + .adder二+ this, addertxt. Text + 1,bnote= + this.notetxt. Text + ; sql2 +=where bisbn=,M + this.bookisbn + ; DataTable dt2 = DBHeIp.ExeOI eCommand(sq12); str i ng sql5 = str ing.Empty; sql5 += Mupdate tb_borrov/ set bna

47、me=， + thisnametxt .Text + bisbn = + this isbntxt.Text + ; sql5 += where bisbn=, + this.bookisbn + ; DataTable dt5 = DBHeIp.ExeOI eCommand(sq15); MessageBox. Show(该矣图书信息修改成功！ ”，提示！ ”); this.checktxt. Text =”； FillGridO; Fill InfoO ; 1 private void FiIIGr id() if (this .checkbox .Text = str ing .Empt

48、y) MessageBox. Show(n请输入你要使用的检索条件！ “，提示！ “)； return; if (this, classbox. Text = str ing .Empty) MessageBox.ShowC1请输入你要查找的图书类型！ ”，提示！ “)； return; str i ng sql = str i ng.Empty; sql += select bid as ID号.bno as 图书编号，bname as 图书名称,bauthor as 作者, be I ass as 类别，bisbn as ISBN 号，boost as 价格,bpub as , adder

49、 as 记录员，adddate as 入库日 期,bnote as 容简介,bstate as 状态 from tb_book; if (this, checktxt. Text !=*) string c = this.checkbox.SelectedlndexToString(); sw i tch (c) case 0H:/图书名称 if (thischecktxtText 匸 string.Empty) sql += v/here bname I ike % + this, checktxt. Text +; break; case T1:/图书编号 if (this.checktx

50、t. Text != string.Empty) sql += where bno Iike + this.checktxt.Text + M; break; case 2:/作者 if (thischecktxtText 匸 string.Empty) sql += v/here bauthor I ike + this. checktxt. Text + break; case 3:/isbn号 if (this.checktxt. Text != string. Empty) sql += v/here bisbn I ike + this, checktxt. Text +; brea

51、k; case 4：/ if (thischecktxt .Text != str ing.Empty) sql += where bpub I ike *+ this, checktxt. Text + break; default: break; if (this, classbox. Selected Index. ToStr ing() != 0) sql += ” and belass=* + thisclassboxText + ; 1 else if (thi s. cI assbox. Se I ectedI ndex. ToStr ing () != 0) sql += ”

52、v/here belass=*M + this classbox. Text + ; 1 sql += ” order by bno asc”； DataTable dt = DBHeIp. ExeOIeCommand(sqI); th i s. dataGr i dV i ev/1. DataSource = dt; 1 private void Fill Info() this, label 3.Text = this.dataGridView11, this. dataGr idVi ev/1. CurrentCe 11. Row I ndex. Value. ToStr ing ().

53、 Tr im(); this, isbntxt.Text = this.dataGr idView15, this. dataGr idViev/1. CurrentCeI I. Roy/Index. Value. ToStr ing(). Tr im(); this, nametxt. Text = this. dataGr idViev/1 2, this. dataGr idVi ev/1. CurrentCe 11. Row I ndex. Value. ToStr ing (). Tr im(); this. classtxt. Text = this.dataGridViewl4,

54、 this. dataGr idViev/1. CurrentCe 11. Row I ndex. Value. ToStr ing (). T r i m (); this. costtxt. Text = thi s.dataGr idView16. this. dataGr idViev/1. CurrentCe I I. Row I ndex. Value. ToStr ing (). Tr im(); this. wr itertxt. Text = this.dataGr idView13. this. dataGr idViev/1. CurrentCe 11. Row I nd

55、ex. Value. ToStr ing (). T r i m (); this, pubtxt. Text = this.dataGridView17, this. dataGr idViev/1. CurrentCe I I. Row Index. Value. ToStr ing(). Tr im(); this, addertxt. Text = this. dataGr idViev/1 8r this. dataGr idViev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr im(); this, notetxt. T

56、ext = this. dataGr idViev/1 lOt this. dataGr idViev/1. CurrentCe 11. Row Index. Value. ToStr i ng (). Tr im(); this isbntxt.Enabled = true: this. nametxt. Enabled = true: th i s. cI asstxt. Enab Ied = true; thiscosttxtEnabled = true; this, wr itertxt. Enabled = true; thispubtxt. Enabled = true; this

57、notetxt .Enabled = true; thisbookisbn 二 this isbntxt .Text; 1 1 7. 用户信息添加 主要代码： pub Iic partial class RegisterForm : Form pub I ic Regi sterFormO InitializeComponent(); ) private void regbtn_CIick(object sender, EventArgs e) if (this, usernametxt. Text = string.Empty) MessageBox.ShowC请输入用户!”提示！ ”）；

58、return; if (this sextxt Text= str ing Empty) MessageBox.ShowC1请输入用户性别! M提示！ ”)； return; 1 if (thispartcob .Text = str i ng.Empty) MessageBox.ShowC请输入用户所在部门！ “，”提示！ ”)； return; 1 if (thistel phonetxtText = str i ng.Empty) MessageBox.ShowC*请输入用户移动！ “，”提示！ ”)； return; if (thisphonetxt .Text = str ing .

59、Empty) MessageBox.ShowC1请输入用户固定！提示！ ”)； return; string patl = 0-刃8,11$”； bool ml = Program. match (thisteIphonetxt .Text, patl); bool m2 = Program.match(thisphonetxtText, patl); if (!m1) MessageBox.ShowC为8到11伎的正整数提示！ ”)； return; if (!m2) MessageBox.ShowC1 为 8到 11 位的正签数！”提示！); return; ) string sq = s

60、tring.Empty; sq += select * from tb_user; sq += ” where uname=*1+this.usernametxtText+ and upart=， +thispartcob.Text* and uteI phone二+thi s teIphonetxt Text* ; DataTable d = DBHeIp. ExeOIeCommand(sq); bool b = false; while (d. Rows. Count = 0) b = true; break; if (b) string sql = string.Empty; sql +