Delphi 7：ADO，需要基本的编码示例 [英] Delphi 7: ADO, need basic coding example

问题描述

我是一个完整的初学者。有人可以发布一些Delphi代码到

• 创建一个数据库


• 添加一个简单的表
• 
  
• 关闭数据库

然后，稍后

• 打开数据库


• 阅读每个表


• 读取给定表格的每个字段


• 执行一个简单的搜索

对不起，这么无聊。我做了google，但没有找到有用的教程...

另外，如果底层数据库是MySql（5.1.36）（I甚至不知道是否有任何差异）

解决方案

@mawg，我为您写了一个简单的程序来阻止工作如何与ADO和德尔福。这是一个控制台应用程序，但解释了基础。

在执行此代码之前，您必须从此位置。

您可以改进和调整此代码

 程序ProjectMysqlADO; 
 
 {$ APPTYPE CONSOLE} 
 
使用
 ActiveX，
 DB，
 ADODB，
 SysUtils; 
 
 const 
 //连接字符串
 StrConnection ='Driver = {MySQL ODBC 3.51 Driver}; Server =％s; Database =％s; User =％s; Password =％s; Option = 3;'; 
 
 
 var 
 AdoConnection：TADOConnection; 
 
程序SetupConnection（DataBase：String）; //打开连接
 begin 
 Writeln（'Connecting to MySQL'）; 
 AdoConnection：= TADOConnection.Create（nil）; 
 AdoConnection.LoginPrompt：= False; //不要求登录参数
 AdoConnection.ConnectionString：=格式（StrConnection，['your_server'，DataBase，'your_user'，'your_password']）; 
 AdoConnection.Connected：= True; //打开连接
 Writeln（'Connected'）; 
结束
 
程序CloseConnection; //关闭一个打开的连接
 begin 
 Writeln（'关闭连接到MySQL'）; 
如果AdoConnection.Connected然后
 AdoConnection.Close; 
 AdoConnection.Free; 
 Writeln（'Connection closed'）; 
结束
 
程序CreateDatabase（Database：string）; 
 begin 
 Writeln（'创建数据库'+数据库）; 
 AdoConnection.Execute（'CREATE DATABASE IF NOT EXISTS'+ Database，cmdText）; 
 Writeln（'Database'+ database +'created'）; 
结束
 
 procedure CreateTables; 
 begin 
 Writeln（'Creating Tables'）; 
 AdoConnection.Execute（
'CREATE TABLE IF NOT EXISTS customers（'+ 
'id INT，'+ 
'name VARCHAR（100），'+ 
'国家VARCHAR（25））'，cmdText）; 
 Writeln（'Tables Created'）; 
结束
 
 
程序DeleteData; 
 begin 
 Writeln（'删除虚拟数据'）; 
 AdoConnection.Execute（'DELETE FROM customers'）; 
 Writeln（'Data deleted'）; 
结束
 
 procedure InsertData; 
 
过程InsertReg（id：integer; name，country：string）; 
 var 
 ADOCommand：TADOCommand; 
 begin 
 ADOCommand：= TADOCommand.Create（nil）; 
 try 
 ADOCommand.Connection：= AdoConnection; 
 ADOCommand.Parameters.Clear; 
 ADOCommand.CommandText：='INSERT INTO customers（id，name，country）VALUES（：id，：name，：country）'; 
 ADOCommand.ParamCheck：= False; 
 ADOCommand.Parameters.ParamByName（'id'）。Value：= id; 
 ADOCommand.Parameters.ParamByName（'name'）。Value：= name; 
 ADOCommand.Parameters.ParamByName（'country'）。Value：= country; 
 ADOCommand.Execute; 
 finally 
 ADOCommand.Free; 
结束
结束
 
 begin 
 Writeln（'插入数据'）; 
 InsertReg（1，'Lilian Kelly'，'UK'）; 
 InsertReg（2，'John and Sons'，'USA'）; 
 InsertReg（3，'William Suo'，'USA'）; 
 InsertReg（4，'MARCOTEC'，'UK'）; 
 Writeln（'Data Inserted'）; 
结束
 
 procedure ReadData; 
 var 
 AdoQuery：TADOQuery; 
 begin 
 AdoQuery：= TADOQuery.Create（nil）; 
 try 
 AdoQuery.Connection：= AdoConnection; 
 AdoQuery.SQL.Add（'SELECT * FROM customers'）; 
 AdoQuery.Open; 
而不是AdoQuery.eof do 
 begin 
 Writeln（format（'％s％s％s'，[AdoQuery.FieldByname（'id'）。AsString，AdoQuery.FieldByname（'name '）.AsString，AdoQuery.FieldByname（'country'）。AsString]））; 
 AdoQuery.Next; 
结束
 finally 
 AdoQuery.Free; 
结束
结束
 
 begin 
 CoInitialize（nil）; //调用CoInitialize（）
 try 
 Writeln（'Init'）; 
 try 
 SetupConnection（'mysql'）; //首先连接到mysql数据库，这个数据库总是存在
 CreateDatabase（'Mydb'）; //现在我们创建数据库
 CloseConnection; //关闭原来的连接
 SetupConnection（'Mydb'）; //打开指向Mydb数据库的连接
 CreateTables; //创建样本表
 DeleteData; //删除伪数据插入
 InsertData; //插入一个虚拟数据
 ReadData; //读取插入的数据
 CloseConnection; //关闭连接
除了
在E：Exception do 
 Writeln（E.Classname，'：'，E.Message）; 
结束
 Readln; 
 finally 
 CoUnInitialize; // free memory 
 end; 
结束。 
  

I am a complete beginner here. Can someone please post some Delphi code to

• create a database
• add a simple table
• close the database

then, later

• open a database
• read each table
• read each field of a given table
• perform a simple search

Sorry to be so clueless. I did google, but didn't find a useful tutorial ...

In addition, it would be useful if the underlying database were MySql (5.1.36) (I don't even know if that makes any difference)

解决方案

@mawg, i wrote an simple program for you to ilustrate how work with ADO and Delphi. this is an console application, but explains the basics.

before you execute this code you must download and install the odbc connector from this location.

You can improve and adapt this code to your requirements.

program ProjectMysqlADO;

{$APPTYPE CONSOLE}

uses
  ActiveX,
  DB,
  ADODB,
  SysUtils;

const
//the connection string
StrConnection='Driver={MySQL ODBC 3.51 Driver};Server=%s;Database=%s;User=%s; Password=%s;Option=3;';


var
AdoConnection : TADOConnection;

procedure SetupConnection(DataBase:String);//Open a connection
begin
  Writeln('Connecting to MySQL');
  AdoConnection:=TADOConnection.Create(nil);
  AdoConnection.LoginPrompt:=False;//dont ask for the login parameters
  AdoConnection.ConnectionString:=Format(StrConnection,['your_server',DataBase,'your_user','your_password']);
  AdoConnection.Connected:=True; //open the connection
  Writeln('Connected');
end;

procedure CloseConnection;//Close an open connection
begin
  Writeln('Closing connection to MySQL');
  if AdoConnection.Connected then
  AdoConnection.Close;
  AdoConnection.Free;
  Writeln('Connection closed');
end;

procedure CreateDatabase(Database:string);
begin
  Writeln('Creating Database '+database);
  AdoConnection.Execute('CREATE DATABASE IF NOT EXISTS '+Database,cmdText);
  Writeln('Database '+database+' created');
end;

procedure CreateTables;
begin
  Writeln('Creating Tables');
  AdoConnection.Execute(
  'CREATE TABLE IF NOT EXISTS customers ('+
  'id      INT,'+
  'name    VARCHAR(100),'+
  'country VARCHAR(25) )',cmdText);
  Writeln('Tables Created');
end;


procedure DeleteData;
begin
  Writeln('Deleting dummy data');
  AdoConnection.Execute('DELETE FROM customers');
  Writeln('Data deleted');
end;

procedure InsertData;

    Procedure InsertReg(id:integer;name,country:string);
    var
    ADOCommand : TADOCommand;
    begin
      ADOCommand:=TADOCommand.Create(nil);
      try
       ADOCommand.Connection:=AdoConnection;
       ADOCommand.Parameters.Clear;
       ADOCommand.CommandText:='INSERT INTO customers (id,name,country) VALUES (:id,:name,:country)';
       ADOCommand.ParamCheck:=False;
       ADOCommand.Parameters.ParamByName('id').Value      := id;
       ADOCommand.Parameters.ParamByName('name').Value    := name;
       ADOCommand.Parameters.ParamByName('country').Value := country;
       ADOCommand.Execute;
      finally
      ADOCommand.Free;
      end;
    end;

begin
    Writeln('Inserting Data');
    InsertReg(1,'Lilian Kelly','UK');
    InsertReg(2,'John and Sons','USA');
    InsertReg(3,'William Suo','USA');
    InsertReg(4,'MARCOTEC','UK');
    Writeln('Data Inserted');
end;

procedure ReadData;
var
  AdoQuery : TADOQuery;
begin
   AdoQuery:=TADOQuery.Create(nil);
   try
    AdoQuery.Connection:=AdoConnection;
    AdoQuery.SQL.Add('SELECT * FROM customers');
    AdoQuery.Open;
    while not  AdoQuery.eof do
    begin
      Writeln(format('%s %s %s',[AdoQuery.FieldByname('id').AsString,AdoQuery.FieldByname('name').AsString,AdoQuery.FieldByname('country').AsString]));
      AdoQuery.Next;
    end;
   finally
   AdoQuery.Free;
   end;
end;

begin
  CoInitialize(nil); // call CoInitialize()
  try
       Writeln('Init');
       try
         SetupConnection('mysql'); //first will connect to the  mysql database , this database always exist
         CreateDatabase('Mydb'); //now we create the database
         CloseConnection; //close the original connection
         SetupConnection('Mydb'); //open the connection pointing to the Mydb database
         CreateTables; //create a sample table
         DeleteData; //Delete the dummy data before insert
         InsertData; //insert a dummy data
         ReadData; //read the inserted data
         CloseConnection; //close the connection
       except
         on E : Exception do
           Writeln(E.Classname, ': ', E.Message);
       end;
      Readln;
  finally
   CoUnInitialize; // free memory
  end;
end.

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