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C++山寨C#中的DataTable

原作者: [db:作者] 来自: [db:来源] 收藏 邀请
原帖地址:http://www.cnblogs.com/hlxs/archive/2013/05/31/3110036.html

简单介绍一下DataTable。DataTable主要基于表、行、单元格。行用集合包装单元格,表用集合包装行,大致就是这样。DataColumn表示单元格,DataColumn中的字段还挺多的,在实际应用中我们可能只想用它来存一个int型的数据;DataColumnCollection中用一个ArrayList封装DataColumn,表示一些单元格的集合;DataRow直接在DataColumnCollection的基础上提供一些方法,成为行记录。而DataRowCollection则用集合的方式封装DataRow成为表,但它不是以线性、链表等方式,而是基于红黑树RBTree<DataRow>,主要是查询和删除比较方便,而DataTable则是DataRowCollection的封装,对看了DataTable整个实现的大致代码,我不得吐槽一下:这它妈是把牛刀,我们每天用它来切菜,用着还挺方便。DataTable提供了很强大的功能,但是我们基本不需要,有时候基本上是得到一个DataTable,啥都不做,直接绑定,最常用的也就Update和Insert,Select和Delete则次之。当然你会说避免使用DataTable,当然还有人说C#......


OK废话到此结束,今天我想做说的是用C++来实现DataTable。大致思路还是按照C#中的来,功能没有C#中的强大,但增删改查的功能还是有的,基本还是个人练习,把代码放出来跟大家讨论一下。基本上是STL中几个集合的运用。在我的实现在并没有使用红黑树,而是用list<DataRow*>代替了,主要类的头文件如下:


DataColumn的实现代码如下,主要是对几个字段的封装。源码共享



#pragma once
class DataTable;
#include
<iostream>
using namespace std;

template
<typename T>
class TDataColumn
{
public:
TDataColumn():columnName(
string()),caption(string())
{

}

TDataColumn(
const string& _columnName):columnName(_columnName),caption(string())
{

}

virtual ~TDataColumn()
{

}

void Caption(const string& _caption)
{
caption
=_caption;
}
string Caption()
{
return caption.size() ?caption:columnName;
}

void ColumnName(const string& _columnName)
{
columnName
=_columnName;
}
string ColumnName()
{
return columnName;
}

void Value(const T& _value)
{
value
=_value;
}
T Value()
{
return value;
}

int ObjectId()
{
return objectId;
}

void Table(DataTable* tb)
{
table
=tb;
}

DataTable
* Table()
{
return table;
}

string TypeName()
{
return typeid(T).name();
}

protected:
int objectId;
string columnName;
string caption;
T value;
DataTable
* table;
};


class DataColumn:public TDataColumn<string>
{
public:
friend
class DataColumnCollection;
friend
class DataTable;
DataColumn():TDataColumn
<string>()
{
objectId
=++objectCountId;
}

DataColumn(
const DataColumn& dc)
{
*this=dc;
}

DataColumn
& operator=(const DataColumn& dc)
{
objectId
=++objectCountId;
columnName
=dc.columnName;
caption
=dc.caption;
value
=dc.value;
table
=dc.table;
return *this;
}

DataColumn(
const string& _columnName):TDataColumn<string>(_columnName)
{
objectId
=++objectCountId;
}

bool operator==(const DataColumn& dc)
{
return objectId==dc.objectId;
}

bool operator!=(const DataColumn& dc)
{
return objectId!=dc.objectId;
}

bool operator<(const DataColumn& dc)
{
return objectId<dc.objectId;
}

bool operator>(const DataColumn& dc)
{
return objectId>dc.objectId;
}

void Show()
{
cout
<<"columnName:"<<columnName.data()<<",caption:"<<Caption().c_str()<<",value:"<<value.data()<<endl;
}

private:
static volatile int objectCountId;
};



其他文件的头文件如下:



#pragma once
#include
<iostream>
using namespace std;
#include
<assert.h>
#include
<vector>
#include
<list>
#include
<map>
#include
"DataColumn.h"
#include
"StringHelper.h"

class DataColumnCollection;
class DataRow;
class DataRowCollection;
class DataTable;

class DataColumnCollection
{
public:
friend
class DataTable;
friend
class DataRow;
friend
class DataRowCollection;
DataColumnCollection(DataTable
* table);
~DataColumnCollection();
void Add(DataColumn* dc);
void Add(DataColumn* dc,size_t index);

DataColumn
& Add(const string& columnName);

bool Contains(const string& columnName);
void Clear();
size_t Count();
int IndexOf(const string& columnName);

void Remove(DataColumn& dc);
void Remove(const string& columnName);
void RemoveAt(size_t index);

void CopyTo(DataColumnCollection* arr, size_t index);

DataColumn
& operator[](size_t index);
DataColumn
& operator[](const string& columnName);

void Table(DataTable* tb);
DataTable
* Table();
private:
void Add(DataColumn* dc,size_t index,DataColumnCollection* collect);
void RemoveAt(size_t index,DataColumnCollection* collect);
void InitData();
DataColumnCollection();
vector
<DataColumn*> dlist;
map
<int,DataColumn*> nameList;
DataTable
* table;
};

class DataRow
{
public:
friend
class DataTable;
friend
class DataRowCollection;
friend
class DataColumnCollection;
~DataRow();
void Table(DataTable* tb);
DataTable
* Table();

DataColumnCollection
& Columns();
DataColumn
& operator[](size_t index);
DataColumn
& operator[](const string& columnName);
bool operator=(const DataRow& dr);
private:
DataRow();
void Remove(DataColumn& dc);
void RemoveAt(size_t index);
DataColumnCollection
* columns;
DataTable
* table;
int rowId;
static volatile int rowIdCount;
};

class DataRowCollection
{
public:
friend
class DataTable;
friend
class DataColumnCollection;
DataRowCollection(DataTable
* table);
~DataRowCollection();
void Add(DataRow* dc);
void Clear();
size_t Count();
void Remove(DataRow* dc);
void RemoveAt(size_t index);
DataRow
& operator[](size_t index);
void Table(DataTable* tb);
DataTable
* Table();
private:
DataRowCollection();
list
<DataRow*> drlist;
DataTable
* table;
};


class DataTable
{
public:
friend
class DataColumnCollection;
friend
class DataRowCollection;
DataTable();
DataTable(
const string& _tableName);
~DataTable();

DataColumnCollection
& Columns();
DataRowCollection
& Rows();

string TableName();
void TableName(const string& _tableName);
DataRow
& operator[](size_t index);
void Clear();
DataRow
* NewRow();
vector
<DataRow*>* Select(const string& columnName,const string& value) ;
private:
void InitData();
DataColumnCollection
* dcCollect;
DataRowCollection
* drCollect;
string tableName;
};


测试代码如下:



#include <iostream>
using namespace std;
#include
<sstream>
#include
"DataColumn.h"
#include
"DataTable.h"
#include
"OperationTimer.h"

int main( )
{
DataTable dt;
for(size_t i=0;i<10;i++)
{
string s("column");
s.push_back(
char('0'+i));
DataColumn
*dc=new DataColumn(s);
dt.Columns().Add(dc);
}

for(int j=0;j<10;j++)
{
DataRow
* dr=dt.NewRow();
for(int i=0;i<10;i++)
{
string s("row");
s.push_back(
char('0'+j));
s.push_back(
char('0'+i));
(
*dr)[i].Value(s) ;
}
dt.Rows().Add(dr);
}

int rowCount=dt.Rows().Count();
int columnCount=dt.Columns().Count();
cout
<<""<<rowCount<<""<<columnCount<<""<<endl;
rowCount
=rowCount/2;
columnCount
=columnCount/2;
cout
<<""<<rowCount<<""<<columnCount<<"列的值为:"<<dt[rowCount][columnCount].Value().c_str()<<endl;

dt.Columns().Add(
new DataColumn("column10"));
dt.Columns().Add(
new DataColumn("column11"));
cout
<<"新增两列后:"<<endl;
rowCount
=dt.Rows().Count();
columnCount
=dt.Columns().Count();
cout
<<""<<rowCount<<""<<columnCount<<""<<endl;
rowCount
=rowCount/2;
columnCount
=columnCount/2;
cout
<<""<<rowCount<<""<<columnCount<<"列的值为:"<<dt[rowCount][columnCount].Value().c_str()<<endl;
cout
<<"删除一行一列后:"<<endl;
dt.Columns().RemoveAt(
4);
dt.Rows().RemoveAt(
2);

rowCount
=dt.Rows().Count();
columnCount
=dt.Columns().Count();
cout
<<""<<rowCount<<""<<columnCount<<""<<endl;
rowCount
=rowCount/2;
columnCount
=columnCount/2;
cout
<<""<<rowCount<<""<<columnCount<<"列的值为:"<<dt[rowCount][columnCount].Value().c_str()<<endl<<endl;

cout
<<"查询列名为column3,值为row43的行,数据如下:"<<endl;
vector
<DataRow*>* vect=dt.Select("column3","row43");
for(size_t i=0;i<vect->size();i++)
{
DataColumnCollection
& dcCollect= (*vect)[i]->Columns();
for(size_t j=0;j<dcCollect.Count();j++)
{
dcCollect[j].Show();
}
}
delete vect;



getchar();
return 0;
}


 结构截图:


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