大数据分析-Delphi数据库编程

Delphi数据库编程1主要内容Delphi简介Ojbect

Pascal语法基础Delphi控件编程Delphi的数据库操作控件Delphi数据库ADO编程2Delphi简介3使用Object

Pascal语言通过控件拖放直接创建Windows应用可快速编写数据库应用程序Object

Pascal语法基础4主要数据类型变量定义与赋值程序控制语句ifwhilefor过程与函数语法基础—主要数据类型5数据类型范围字节数说明Integer-2147483648~21474836474整型int64-263~263-1864位整型Boolean0或11布尔型String长度没有限制字符串Record记录Pointer指针语法基础—常用运算符6赋值：:=比较：=,<>,>,<,>=,<=逻辑：and,or,not算数运算：+,-,*,/,div,mod字符串合并：+语法基础—注释方法7{......}(*......*)//......编写字符界面应用file->new->other...->选择Console

Application8语法基础—变量定义与赋值9program

ProjTest;{$APPTYPE

CONSOLE}usesSysUtils;//////////////////////////////

以上为自动生成部分var

a,b,c:integer;

//变量定义begin{

TODO

-oUser

-cConsole

Main

:

Insert

code

here

}//变量赋值//显示结果//等待输入a:=1;b:=2;c:=a+b;writeLn(IntToStr(c));readLn;end.语法基础—if语句10var

a,b:integer;begina:=1;b:=2;if(a>b)

thenwriteLn(IntToStr(a))elsewriteLn(IntToStr(b));readLn;end.语法基础—while语句writeLn(IntToStr(sum));readLn;end.11var

i,sum:integer;begini:=1;sum:=0;while

i<=100

dobeginsum:=sum+i;i:=i+1;end;语法基础—for语句writeLn(IntToStr(sum));readLn;end.12var

i,sum:integer;begini:=1;sum:=0;for

i:=1

to

100

dobeginsum:=sum+i;//i:=i+1;end;Delphi控件编程—简介13控件编程--显示“Hello,world.”1.新建“Application”2.把按钮控件，拖到窗体上143.双击按钮，编写代码procedure

TForm1.Button1Click(Sender:

TObject);beginShowMessage("Hello,world!");end;4.运行155.运行结果16在窗体和代码编辑器间切换17控件编程—加法计算器编辑框：num1Edit，num2Edit标签：sumLab按钮：button118按钮单击事件对应代码19procedure

TForm1.Button1Click(Sender:

TObject);var

n1,n2,sum:integer;beginn1:=StrToInt(num1Edit.text);n2:=StrToInt(num2Edit.Text);sum:=n1+n2;sumLab.Caption:=IntToStr(sum);end;练习20用两个整数指定范围求这个范围内自然数的和procedure

TForm1.Button1Click(Sender:

TObject);var

i,n1,n2,sum:integer;beginn1:=StrToInt(num1Edit.text);n2:=StrToInt(num2Edit.Text);sum:=0;for

i:=n1

to

n2

dobeginsum:=sum+i;end;sumLab.Caption:=IntToStr(sum);12.end;21数据库编程22简介主要方式使用ADO使用ADO23ODBC，OLEDB，ADO介绍连接数据库执行SQL显示查询结果ADO控件24ADO—使用ADOConnection控件dbExpress25ADO—设置连接字符串26procedure

TForm1.FormCreate(Sender:

TObject);beginconn.ConnectionString:="Provider=SQLOLEDB.1;"+"Password=sa;"+"Persist

Security

Info=True;"+"User

ID=sa;"+"Initial

Catalog=law;"+"Data

Source=LAW-PC";10.end;ADO—连接数据库procedure

TForm1.Button1Click(Sender:

TObject);beginconn.Open（）;if

conn.Connected=true

thenconnStatusLbl.Caption:="Connected."elseconnStatusLbl.Caption:="Connection

failed.";end;27TADOQuery控件28执行SQL语句aqurey1.SQL.clearaqurey1.SQL.add(‘......’)aquery1.active:=trueaqurey1.open：与active设置为true相同aquery1.closeaquery1.executeSQL：执行DML语句执行DML语句procedure

TForm1.Button1Click(Sender:

TObject);beginaQuery.SQL.Clear;aQuery.SQL.Add("insert

into

t

values(3,30)");aQuery.ExecSQL;end;29TADODataSet控件30负责取回记录集设置连接属性只能执行查询，不能执行数据修改commandText属性设置要执行的SQL语句ADO—显示表中数据31添加下面四个控件conn：ADOConnectionloginPrompt设置为false在代码中设置连接字符串和open操作adoDset：ADODataSetconnection属性设置为conndSource：ADODataSourcedataset属性设置为adoDsetdGrid：DBGriddatasource属性设置为dSourceTADODataSet控件32执行查询显示结果33procedure

TForm1.Button1Click(Sender:

TObject);beginds.Active:=false;ds.CommandText:=SQLEdit.Text;（ds.CommandText:=‘select*from

’;）ds.Active:=true;end;登录验证34unit1implementation{$R

*.dfm}uses

unit2;procedure

TForm1.FormCreate(Sender:

TObject);beginconn.ConnectionString:="Provider=SQLOLEDB.1;"+"Password=sa;"+"Persist

Security

Info=True;"+"User

ID=sa;"+"Initial

Catalog=law;"+"Data

Source=LAW-PC";conn.Open();11.end;procedure

TForm1.FormShow(Sender:

TObject);beginform2.ShowModal;end;35unit2implementation{$R

*.dfm}uses

unit1;procedure

TForm2.FormCreate(Sender:

TObject);beginds.Connection:=form1.conn;end;36procedure

TForm2.Button1Click(Sender:

TObject);varuser,passwd:String;beginuser:=userEdit.Text;

passwd:=passwdEdit.Text;ds.Active:=false;ds.CommandText:="select

*

from

t

where

a="+user+"and

b="+passwd;ds.Active:=true;if

(ds.RecordCount>0)

thenbeginform2.Close;endelse

showMessage("UserID

or

Password

is

not

correct.");end;37procedure

TForm2.FormClose(Sender:

TObject;

var

Action:

TCloseAction);beginform1.Close;end;38把查询结果赋值给变量39使用TADOQuery控件procedure

TForm1.Button1Click(Sender:

TObject);var

a,b,c,d:integer;beginaQuery.Close;aQuery.SQL.Text:="select

count(*)

as

cnt

from

t

where

a=2";aQuery.open;a:=aQuery.FieldValues["cnt"];//b:=aQuery.FieldValues["B"];//c:=aQuery.Fields[0].AsInteger;showMessage(intToStr(a));end;使用TADODataset控件40procedure

TForm1.Button1Click(Sender:

TOb