drop_index.cpp

小型数据库源代码较多

#include "min.h"

void sql::drop_index( )
{
	try
	{
		int i = 0;
		cin >> index;
		if( index.find(';')==-1)
			throw 1;
		index.assign(index.c_str(),index.size()-1);
		Table* table;
		Col* col;	
		//看索引是否存在
		table = tablehead;
		while ( table->next )
		{
			table = table->next;
			col = table->collist;
			while ( col->next )
			{
				col = col->next;
				if ( col->indexname == index  ) 
				{
					i++;
					char del[50] = "del ";
					fileload = table->name +"_" + index + ".idx";
					strcat( del,fileload.c_str());
					system ( del );//删索引
					col->indexname = "";
				}
			}
		}
		if( i == 0 )
			throw 2;
		cout << "索引<"+index+">删除成功！ " << endl;		
	    	Log("索引<"+index+">删除成功！");//pp
	}
	catch( int i )
	{
		switch ( i )
		{
			case 1: cout << "语法错误！" << endl;
					break;
			case 2: cout << "索引不存在！" <<endl;
					break;
		
		    
		
		}
		Log("索引<"+index+">删除失败！");//pp
		char a[50];
		cin.getline( a, 50 );
	}
}