数据库设计源代码

资料范本本资料为word版本，可以直接编辑和打印，感谢您的下载数据库设计源代码地点： 时间： 说明：本资料适用于约定双方经过谈判，协商而共同承认，共同遵守的责任与义务，仅供参考，文档可直接下载或修改，不需要的部分可直接删除，使用时请详细阅读内容〃选择一种高级语言实现下列语句的功能。//CREATETABLE〈表名〉(〈列名＞＜数据类型＞[＜列完整性约束条件＞][,＜列名＞＜数据〃类型＞[＜列完整性约束条件＞]•••][，〈表完整性约束条件〉])//ALTERTABLE〈表名〉[ADD〈新列名＞＜数据类型＞[〈列完整性约束＞]][DROP＜列完整//性约束名＞][MODIFY〈列名＞＜数据类型〉]〃使用说明//1、将程序文件table.sql放在D盘根目录下。//2、在C盘根目录下建立一个名为〃数据库〃的文件夹，用于存储表。//3、建立的表存储路径为C:\数据库：\table.dbf。//4、在程序文件table.sql中只有一条建表语句和三条修改表语句，在以程序方式执//行时注意执行的次数，慎重选择“是否继续执行”。//5、程序输入的SQL语句格式如下：//createtablestudent//(//SNOintPRIMARYKEY,//SNAMEchar(10)UNIQUE,//SAGEint,//SDEPTchar(20)NOTNULL,//COURSEchar(20),//GRADEint//)；//altertablestudentaddCNOintNOTNULL;//altertablestudentaltercolumnSAGEshort;//altertablestudentdropSDEPT;#include<stdio.h>#include<stdlib.h>#include<string.h>#include<conio.h>//宏定义#defineYEAR0#defineMONTH1#defineDAY2#defineFOX_VERISON_INFO262#defineMAX40〃字段类型TOC\o"1-5"\h\z#define DATE 0x44#define DOUBLE 0x45#define FLOAT 0x46#define SHORT 0x47#define INT 0x48#define TRUE 1#define FALSE 0〃文件头结构体定义structDbfHead(chardbFlag;charyear;charmonth;charday;intrecCounts;shortfirstRecAddr;shortrecLen;charundo[20];}；typedefstructDbfHeadDbfHead,*pDbfHead;//字段描述结构体定义structFieldDcp(charfieldName[10];charundo1;charfieldType;shortoffset;charundo2[2];charfieldLen;charnumDecis;charundo3[14];};typedefstructFieldDcpFieldDcp,*pFieldDcp;//字段数据结构体定义structDbfField(char*fieldData;charfieldName[10];charfieldType;charfieldLen;charfieldDcis;shortoffset;}；typedefstructDbfFieldDbfField,*pDbfField;//记录结构体定义structDbfRec(chardelFlag;DbfFieldfield[MAX];intrealCounts;};typedefstructDbfRecDbfRec,*pDbfRec;//dbf文件句柄定义structDbfHand(charfilename[50];DbfHeadheader;DbfRecrec;longcurRecNo;longcurFpAddr;FILE*fd;};typedefstructDbfHandDbfHand,*pDbfHand;〃约束条件typedefstructCondition(intflag;//flag用于区分约束条件(PARIMARYKEY1UNIQUE2NOTNULL3)}Condition;pDbfHandf;DbfRecrec;chartable_name[20];charsql[300],sql1[300];charGetDate(intgetMode)//获取日期(if(DAY==getMode)return01;if(MONTH==getMode)return06;if(YEAR==getMode)return10;elseexit(0);}shortGetHeadLength(pDbfRecrec)//获得文件头长度(returnrec->realCounts*32+32+2;}shortGetRecLength(pDbfRecrec)//获得文件体长度registerinti=0;intcount=0;for(i=0;i<rec->realCounts;i++)(if(rec->field[i].fieldType=='D')(count+=8;continue;}elseif(rec->field[i].fieldType=='I')(count+=4;continue;}elseif(rec->field[i].fieldType=='T')(count+=6;continue;}count+=rec->field[i].fieldLen;}returncount+1;}pDbfHandNewDbfHead(pDbfHandhand,pDbfRecrec)//新建文件头intret=-1;hand->header.dbFlag=0x03;hand->header.day=GetDate(DAY);hand->header.month=GetDate(MONTH);hand->header.year=GetDate(YEAR);hand->header.recLen=GetRecLength(rec);hand->header.recCounts=0;hand->header.firstRecAddr=GetHeadLength(rec);if(0!=fseek(hand->fd,0,SEEK_SET))returnNULL;ret=fwrite((char*)&hand->header,sizeof(DbfHead),1,hand->fd);if(ret!=-1)returnhand;elsereturnNULL;}pDbfHandUpdateHead(pDbfHandhand)//更新文件头(if(0!=fseek(hand->fd,0,SEEK_SET))returnNULL;if(-1==fwrite((char*)&hand->header,sizeof(DbfHead),1,hand->fd))returnNULL;fclose(hand->fd);returnhand;}pDbfHandWriteFieldDicsribe(pDbfHandhand,pDbfRecrec)//写字段描述部分(inti=0;FieldDcpfield={0};field.offset=0x01;for(i=0;i<rec->realCounts;i++)(field.fieldType=rec->field[i].fieldType;field.numDecis=0;switch(field.fieldType)(caseDOUBLE:field.fieldLen=8;break;caseFLOAT:field.fieldLen=4;break;caseINT:field.fieldLen=4;break;caseSHORT:field.fieldLen=2;break;default:field.fieldLen=rec->field[i].fieldLen;break;}strcpy(field.fieldName,rec->field[i].fieldName);field.offset+=(short)rec->field[i].fieldLen;if(-1==fwrite((char*)&field,sizeof(FieldDcp),1,hand->fd))returnNULL;}hand->rec.delFlag=0x20;hand->rec.realCounts=rec->realCounts;for(i=0;i<rec->realCounts;i++)hand->rec.field[i]=rec->field[i];returnhand;}voidWriteFieldEnd(pDbfHandhand)//写文件头结束标志(inti=0;charbuf[2]=(0x0D,0x00};charversionBuf[FOX_VERISON_INFO]={0};if(0==fseek(hand->fd,0,SEEK_END)){if(-1==fwrite(buf,2,1,hand->fd))return;return;}pDbfHandReadDbfHead(pDbfHandhand)//读文件头信息(inti=0,j=0;if(-1!=(fseek(hand->fd,0,SEEK_SET)))(if(0!=fread((char*)&hand->header,32,1,hand->fd))returnhand;}returnNULL;}intGetFieldCount(pDbfHandhand)//得到字段个数(inti=0;intoffset=1;FieldDcpfield={0};charcEnd=0;for(i=0;i<MAX;i++)(memset((char*)&field,0,sizeof(FieldDcp));if(-1==fseek(hand->fd,(i+1)*32,SEEK_SET))return-1;if(0!=fread((char*)&field,32,1,hand->fd))fread(&cEnd,1,1,hand->fd);if(0x0D==cEnd)return(i+1);}}return-1;}pDbfHandReadFieldDiscribe(pDbfHandhand)//读字段描述信息(inti=0,j=0;intfieldCount=GetFieldCount(hand);hand->rec.realCounts=fieldCount;for(i=0;i<hand->rec.realCounts;i++)(FieldDcpfield={0};if(-1==fseek(hand->fd,(i+1)*32,SEEK_SET))returnNULL;if(-1==fread((char*)&field,32,1,hand->fd))returnNULL;memcpy(hand->rec.field[i].fieldName,field.fieldName,sizeof(field.fieldName));hand->rec.field[i].fieldLen=field.fieldLen;hand->rec.field[i].fieldType=field.fieldType;hand->rec.field[i].fieldDcis=field.numDecis;hand->rec.field[i].offset=field.offset;}for(i=0;i<hand->rec.realCounts;i++)(for(j=0;hand->rec.field[i].fieldName[j]!='\0';j++)(hand->rec.field[i].fieldName[j]=tolower(hand->rec.field[i].fieldName[j]);}}returnhand;}char*SaveDate(char*str)//保存内容为日期时，格式华(inti=0,j=0;chartemp[9]={0};if(strlen(str)!=10) //日期格式输入不合法returnNULL;for(i=0,j=0;i<10;i++)(if(i==4||i==7)continue;else(if(*(str+i)>='0'&&*(str+i)<='9')temp[j]=*(str+i);j++；}elsereturnNULL;}}str=NULL;str=(char*)realloc(str,8);memset(str,0x00,8);memcpy(str,temp,8);returnstr;}intWriteRecord(pDbfHandhand,pDbfRecrecord)//在当前位置写一条纪录,覆盖原有内容(inti=0;char*buf=NULL;intcurFieldLen=0;intactDataLen=0;intnPos=1;intnFiledCount=0;intrest=TRUE;nFiledCount=hand->rec.realCounts;buf=(char*)malloc(hand->header.recLen+1);buf=memset(buf,0x20,hand->header.recLen+1);buf[0]='';for(i=0;i<nFiledCount;i++)(if(hand->rec.field[i].fieldType==DATE&&record->field[i].fieldData!=NULL)record->field[i].fieldData=SaveDate(record->field[i].fieldData);curFieldLen=hand->rec.field[i].fieldLen;actDataLen=strlen(record->field[i].fieldData);if(actDataLen>curFieldLen)actDataLen=curFieldLen;memcpy(&buf[nPos],record->field[i].fieldData,actDataLen);nPos+=hand->rec.field[i].fieldLen;}buf[hand->header.recLen]='\0';if(-1==fwrite(buf,hand->header.recLen,1,hand->fd))rest=FALSE;returnrest;}char*ReadDbfDate(char*str)//读日期时，格式化(inti=0,j=0;chartemp[11]={0};char*strRest=NULL;for(i=0,j=0;i<8;i++,j++)(if(i==4||i==6)(temp[j]=，/，;j++；}temp[j]=*(str+i);}str=(char*)calloc(11,sizeof(char));memset(str,0x00,11);memcpy(str,temp,10);returnstr;}char*DsdStrEndSpace(char*str,intsize)//去掉字符串的后面空格(inti=0,flag=0;for(i=size-1;i>=0;i--)(if(*(str+i)!=0x20)break;str[i]=0x00;}returnstr;/*pDbfFieldGetCurrentField(pDbfHandhandle,pDbfRecrec,intfieldId)//得到当前文件(return(pDbfField)&(rec->field[fieldId]);}*/intGetFieldNum(pDbfHandhand,char*field_name)//得到文件个数(intflag=0;intj;for(j=0;j<hand->rec.realCounts;j++)(if(0==strcmp(field_name,hand->rec.field[j].fieldName))(flag=1;break;}}if(flag)returnj;elsereturn-1;}intIsBottomRecord(pDbfHandhand)//判断是否是第一条记录(intrecCounts=hand->header.recCounts;if(hand->curRecNo!=hand->header.recCounts)returnFALSE;returnTRUE;}intGotoTop(pDbfHandhand)//返回顶部(hand->curRecNo=1;hand->curFpAddr=hand->header.firstRecAddr;if(-1==fseek(hand->fd,hand->curFpAddr,SEEK_SET))returnFALSE;returnTRUE;}intGotoBottom(pDbfHandhand)//移动到最后一条记录(intrecLen=hand->header.recLen;longoffset=0;offset=recLen*(hand->header.recCounts-1);hand->curRecNo=hand->header.recCounts;hand->curFpAddr=hand->header.firstRecAddr+offset;if(-1==fseek(hand->fd,hand->curFpAddr,SEEK_SET))returnFALSE;returnTRUE;}intGoNextRecord(pDbfHandhand)//移动到下一条记录if(TRUE==IsBottomRecord(hand))returnTRUE;else(hand->curRecNo+=1;hand->curFpAddr+=hand->header.recLen;if(-1==fseek(hand->fd,hand->header.recLen,SEEK_CUR))returnFALSE;}returnTRUE;}intGetCurRecord(pDbfHandhand,pDbfRecrec)//得到当前记录(inti=0,m;charcurFieldLen=0;longfieldOffset=0;charpBuffData[1024]={0};char*recData;(*rec)二hand->rec;for(m=0;m<hand->rec.realCounts;m++){rec->field[m].fieldData=(char*)malloc(hand->rec.field[m].fieldLen+1);memset(rec->field[m].fieldData,0x00,hand->rec.field[m].fieldLen+1);if(-1==fseek(hand->fd,hand->curFpAddr,SEEK_SET))//Movefilepointerreturn0;recData=pBuffData;recData=recData+1;if(-1==fread(recData,hand->header.recLen,1,hand->fd))return0;rec->delFlag=recData[0];recData=recData+1;for(i=0;i<hand->rec.realCounts;i++,fieldOffset+=curFieldLen)(curFieldLen=hand->rec.field[i].fieldLen;memcpy(rec->field[i].fieldData,recData+fieldOffset,curFieldLen);rec->field[i].fieldData=DsdStrEndSpace(rec->field[i].fieldData,curFieldLen);if(rec->field[i].fieldType==DATE&&rec->field[i].fieldData[0]!=0x20)rec->field[i].fieldData=ReadDbfDate(rec->field[i].fieldData);}return1;}pDbfHandAddRec(pDbfHandhand,pDbfRecrecord)//向文件尾中插入一条记录(chardataEndFlag=0x1A;if((hand->fd=fopen("c:\\数据库\\table.dbf〃，〃r+b〃))==NULL)returnNULL;if(hand->header.recCounts==0)fseek(hand->fd,-0L,SEEK_END);elsefseek(hand->fd,-1L,SEEK_END);if(FALSE==WriteRecord(hand,record))returnNULL;if(-1==fwrite(&dataEndFlag,1,1,hand->fd))returnNULL;hand->curRecNo+=1;hand->header.recCounts+=1;hand->curFpAddr+=hand->header.recLen;if(NULL==UpdateHead(hand))returnNULL;returnhand;}pDbfHandAddField(pDbfHandhand,char*field_name,chartype,intlen,intdec)//在文件中插入一条记录(inti,reccounts;pDbfRec*rec;if(hand->header.recCounts)rec=(pDbfRec*)malloc(sizeof(pDbfRec)*hand->header.recCounts);hand->curFpAddr二hand->header.firstRecAddr;hand->curRecNo=1;if(-1==fseek(hand->fd,hand->curFpAddr,SEEK_SET))returnFALSE;for(i=0;i<hand->header.recCounts;i++)(rec[i]=(pDbfRec)malloc(sizeof(DbfRec));GetCurRecord(hand,rec[i]);GoNextRecord(hand);}for(i=0;i<hand->header.recCounts;i++)(rec[i]->field[hand->rec.realCounts].fieldData=(char*)malloc(len+1);memset(rec[i]->field[hand->rec.realCounts].fieldData,0x00,len+1);rec[i]->realCounts++;}}strcpy(hand->rec.field[hand->rec.realCounts].fieldName,field_name);hand->rec.field[hand->rec.realCounts].fieldName[strlen(field_name)]='\0';hand->rec.field[hand->rec.realCounts].fieldType二type;hand->rec.field[hand->rec.realCounts].fieldLen=len;hand->rec.field[hand->rec.realCounts].fieldDcis二dec;hand->rec.realCounts++;reccounts二hand->header.recCounts;hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w〃)；fclose(hand->fd);hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w+b〃)；if(NewDbfHead(hand,&hand->rec)==NULL)returnNULL;if(NULL==WriteFieldDicsribe(hand,&hand->rec))returnNULL;WriteFieldEnd(hand);if(0!=fclose(hand->fd))returnNULL;for(i=0;i<reccounts;i++)AddRec(hand,rec[i]);returnhand;}pDbfHandAlterField(pDbfHandhand,char*field_name,chartype,intlen,intdec)//修改一条记录(intnum,i,reccounts;pDbfRec*rec;num二GetFieldNum(hand,field_name);if(hand->header.recCounts)(rec=(pDbfRec*)malloc(sizeof(pDbfRec)*hand->header.recCounts);hand->curFpAddr=hand->header.firstRecAddr;hand->curRecNo=1;if(-1==fseek(hand->fd,hand->curFpAddr,SEEK_SET))returnFALSE;for(i=0;i<hand->header.recCounts;i++)(rec[i]=(pDbfRec)malloc(sizeof(DbfRec));GetCurRecord(hand,rec[i]);GoNextRecord(hand);rec[i]->field[num].fieldDcis二dec;rec[i]->field[num].fieldLen=len;rec[i]->field[num].fieldType二type;}}hand->rec.field[num].fieldType二type;hand->rec.field[num].fieldLen=len;hand->rec.field[num].fieldDcis二dec;reccounts二hand->header.recCounts;hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w〃)；fclose(hand->fd);hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w+b〃)；if(NewDbfHead(hand,&hand->rec)==NULL)returnNULL;if(NULL==WriteFieldDicsribe(hand,&hand->rec))returnNULL;WriteFieldEnd(hand);if(0!=fclose(hand->fd))returnNULL;for(i=0;i<reccounts;i++)AddRec(hand,rec[i]);returnhand;}pDbfHandDropField(pDbfHandhand,char*field_name,intn)//删除一条记录(intnum,i,j,reccounts;pDbfRec*rec;num二GetFieldNum(hand,field_name);if(hand->header.recCounts)(rec=(pDbfRec*)malloc(sizeof(pDbfRec)*hand->header.recCounts);hand->curFpAddr=hand->header.firstRecAddr;hand->curRecNo=1;if(-1==fseek(hand->fd,hand->curFpAddr,SEEK_SET))returnFALSE;for(i=0;i<hand->header.recCounts;i++)rec[i]=(pDbfRec)malloc(sizeof(DbfRec));GetCurRecord(hand,rec[i]);GoNextRecord(hand);rec[i]->field[num].fieldDcis=rec[i]->field[num+1].fieldDcis;rec[i]->field[num].fieldLen=rec[i]->field[num+1].fieldLen;rec[i]->field[num].fieldType=rec[i]->field[num+1].fieldType;num++;}}if(num==-1)(for(j=0;j<10;j++)hand->rec.field[num].fieldName[j]=0;hand->rec.field[num].fieldType=0;hand->rec.field[num].fieldLen=0;hand->rec.field[num].fieldDcis=0;}else(for(;num<n;num++)(strcpy(hand->rec.field[num].fieldName,hand->rec.field[num+1].fieldName);hand->rec.field[num].fieldType二hand->rec.field[num+1].fieldType;hand->rec.field[num].fieldLen二hand->rec.field[num+1].fieldLen;hand->rec.field[num].fieldDcis二hand->rec.field[num+1].fieldDcis;}}hand->header.recCounts--;reccounts二hand->header.recCounts;hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w〃)；fclose(hand->fd);hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w+b〃)；if(NewDbfHead(hand,&hand->rec)==NULL)returnNULL;if(NULL==WriteFieldDicsribe(hand,&hand->rec))returnNULL;WriteFieldEnd(hand);if(0!=fclose(hand->fd))returnNULL;for(i=0;i<reccounts;i++)AddRec(hand,rec[i]);returnhand;}pDbfHandCreateDbf(DbfRecrec)//建立DBF文件(pDbfHandhand=NULL;if((hand=(pDbfHand)malloc(sizeof(DbfHand)))==NULL)returnNULL;memset(hand,0x00,sizeof(DbfHand));if((hand->fd=fopen("c:\\数据库\\table.dbf〃，〃w+b〃))！=NULL)(if(NewDbfHead(hand,&rec)==NULL)returnNULL;if(NULL==WriteFieldDicsribe(hand,&rec))returnNULL;WriteFieldEnd(hand);}fclose(hand->fd);returnhand;}pDbfHandOpenDbf()//打开DBF文件(pDbfHandhand=NULL;if((hand=(pDbfHand)malloc(sizeof(DbfHand)))==NULL)returnNULL;memset(hand,0x00,sizeof(DbfHand));if((hand->fd=fopen("c:\\数据库\\table.dbf〃，〃r+b〃))==NULL)returnNULL;if(NULL==ReadDbfHead(hand))returnNULL;if(NULL==ReadFieldDiscribe(hand))returnNULL;GotoTop(hand);returnhand;}voidShowBeginning()(printf(〃+ +\n");printf("|l\n");printf("| 欢迎进入SQL系统l\n");printf("||\n");printf("+ +\n");}voidShow()(printf("输入语句格式如下：\n〃）；printf("createtablestudent\n");printf("(\n");printf("SNOintPRIMARYKEY,\n");printf("SNAMEchar(10)UNIQUE,\n〃)；printf("SAGEint,\n〃)；printf("SDEPTchar(20)NOTNULL,\n")printf("COURSEchar(20),\n〃)；printf("GRADEint\n");printf(" );\n");printf(" alter table student addCNOintNOTNULL;\n");printf(" alter table student altercolumnSAGE short;\n");printf(" alter table student dropSDEPT;\n");}intRead()//用于读取从键盘键入的SQL语句(charc;inti,j;printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n〃)；printf("请输入SQL语句:\n\n");for(i=0;(c=getch())!=';';i++)(if(c==27)exit(0);if(c==8)(i-=2;if(i<-1)i=-1;system("cls");Show();printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");printf("请输入SQL语句:\n\n");for(j=0;j<=i;j++)(if(sql1[j]==13)(puts(〃〃)；}printf("%c",sql1[j]);}continue;}sql1[i]=c;if(c==13)(puts(〃〃)；sql[i]='';}elseif(c=二，(，||c=二，)，||c=二，\，，)(printf("%c",c);sql[i]=，，;}else(printf("%c",c);sql[i]=c;}}sql[i]=’；’；sql[i+1]='\0';printf(〃;〃)；puts(〃〃)；return0;}intposition;//文件指针的位置intRead1()//用于读取从程序文件中读取的SQL语句(FILE*fp;charc;inti,j;printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");printf("请输入SQL语句:\n\n");fp二fopen(〃d:\\table.sql〃，〃r〃)；fseek(fp,position,0);for(i=0;(c=fgetc(fp))!=';';i++)(if(c==27)exit(0);if(c==8)i-=2;if(i<-1)i=-1；system("cls");Show();printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n〃)；printf("请输入SQL语句:\n\n");for(j=0;j<=i;j++)(if(sql1[j]==13)puts(〃〃)；printf("%c",sql1[j]);}continue;}sql1[i]=c;if(c==13)(puts(〃〃)；sql[i]='';}elseif(c=二，(，||c=二，)，||c=二，\，，)printf("%c",c);sql[i]=’’；}else(printf("%c",c);sql[i]=c;}}sql[i]=’；’；sql[i+1]='\0';printf(〃;〃)；puts(〃〃)；position二ftell(fp);return0;}intCREATE()(chartype[6][10]={〃char〃,〃int〃,〃short〃,〃float〃,〃double〃};charType1[6]={'C','N','S','F','D'};FILE*fp二NULL;Conditioncon[MAX];//约束条件结构体inti,j,num=0,error=1;//num字段数error输入错误标志chartemp[10],condition[10];//table_name表名condition约束条件memset(con,0,sizeof(con[0])*MAX);//结构体中各值初始化为空for(i=0;sql[i]=='';i++);for(j=0;sql[i]!二’’&&sql[i]!=’；’；i++,j++)temp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,"create")!=0)//判断create是否写错(error=0;printf("\n你输入的’create'有误，请重新创建!\n");}else(for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=';';i++,j++)temp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,"table")!=0)//判断table是否写错(error=0;printf("\n你输入的'table'有误，请重新创建!\n");}else(for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=';';i++,j++)//提取表名table_name[j]=tolower(sql[i]);table_name[j]='.'； //加后缀.dbftable_name[j+1]='d';table_name[j+2]='b';table_name[j+3]='f';table_name[j+4]='\0';do(intfield_lengtf=0,flag=1;//field_lengtf字段长度for(;sql[i]=='，||sql[i]==，,，;i++);if(sql[i]==';')break;for(j=0;sql[i]!=，，;i++,j++)//提取列名rec.field[num].fieldName[j]=sql[i];rec.field[num].fieldName[j]=，\0，;for(;sql[i]==，，;i++);for(j=0;sql[i]!=，，&&sql[i]!二，,，;i++,j++)//提取列数据类型temp[j]=tolower(sql[i]);temp[j]=，\0，;for(j=0;j<5;j++)(if(strcmp(temp,type[j])==0)(rec.field[num].fieldType=Type1[j];break;}if(j==5)//列数据类型有误(error=0;printf("\n你输入的列数据类型有误(务必是char,int,short,float,double)，请重新创建!\n〃)；break;}else(/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/if(rec.field[num].fieldType=='C')(〃如果类型是char需要提取列长度，如果是int、float则固定列长度为4,double则固定列长度为8for(;sql[i]=='';i++);for(;sql[i]!=''；i++)//提取长度(if(sql[i]<48||sql[i]>58)//列长度必须是数字(flag=0;break;}elsefield_lengtf二field_lengtf*10+(sql[i]-48);}if(flag==0)(error=0;printf("\n你输入的列长度有误，请重新创建!\n");break;}elserec.field[num].fieldLen=field_lengtf;}elseif(rec.field[num].fieldType=='N'||rec.field[num].fieldType=='F')rec.field[num].fieldLen=4;elseif(rec.field[num].fieldType=='D')rec.field[num].fieldLen=8;elseif(rec.field[num].fieldType=='S')rec.field[num].fieldLen=2;field_lengtf=0,flag=1;for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=','&&sql[i]!=';';i++,j++)//提取列完整性约束condition[j]=tolower(sql[i]);condition[j]='\0';if(condition[0]!=','&&condition[0]!='\0')(if(strcmp(condition,〃primary〃)==0)//判断是否为主键(for(;sql[i]=='';i++);for(j=0;sql[i]!二’’&&sql[i]!='，’；i++,j++)temp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,〃key〃)==0)con[num].flag=1;else(error=0;printf("\n你输入的'KEY'有误，请重新创建!\n");break;}}elseif(strcmp(condition,"unique")==0)//判断是否取唯一值con[num].flag=2;elseif(strcmp(condition,"not")==0)//判断是否非空(for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=',';i++,j++)condition[j]=tolower(sql[i]);condition[j]='\0';if(strcmp(condition,"null")==0)con[num].flag=3;else(error=0;printf("\n你输入的约束条件'NOTNULL'有误，请重新创建!\n〃)；break;}}else//列完整性约束出错(error=0;printf("\n你输入的约束条件有误(必须PARIMARYKEY,UNIQUE,NOTNULL)，请重新创建!\n〃)；break;}}}rec.field[num].fieldDcis=0;rec.field[num].offset=0;rec.realCounts=num+1;num++;//下一字段}while(sql[i]!二’；’)；if((fp二fopen(〃d:\\student.dat〃，〃w+b〃))==NULL)//将列完整性约束条件写入文件中(printf（"打开文件失败！\n"）;error=0;}fwrite(&con,sizeof(Condition)*num,1,fp);fclose(fp);fp=NULL;}}if(error==0)(memset(sql,0,sizeof(char)*300);//出错时清空输入的语句return0;}else(if(f!二CreateDbf(rec))//建立.dbf文件return1;elsereturn0;}return1;}intALTER()(chartype[6][10]={〃char〃，〃int〃，〃short〃，〃float〃，〃double〃};charType1[6]={'C','N','S','F','D'};FILE*fp;inti,j,num,error=1;charT; 〃列数据类型的简写Conditioncon[MAX];//约束条件结构体chartemp[10],field_name[10],f_type[10],condition[10];//field_name列名f_type列数据类型memset(&con,0,sizeof(con));//结构体中各值初始化为空for(i=0;sql[i]=='';i++);for(j=0;sql[i]!=''；i++,j++)temp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,"alter")!=0)//判断alter是否写错(error=0;printf("\n你输入的'alter'有误，请重新输入SQL语句!\n");}else(for(;sql[i]=='';i++);for(j=0;sql[i]!='';i++,j++)temp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,"table")!=0)//判断table是否写错error=0;printf("\n你输入的’table'有误，请重新输入SQL语句！\n");}else(for(;sql[i]=='';i++);for(j=0;sql[i]!='';i++,j++)//提取表名table_name[j]=tolower(sql[i]);table_name[j]='.'； //加后缀.dbftable_name[j+1]='d';table_name[j+2]='b';table_name[j+3]='f';table_name[j+4]='\0';if((f=OpenDbf())==0)〃判断该表是否存在(printf("\n你输入的表%s不存在，请重新输入SQL语句！\n”,table_name);error=0;}else(for(;sql[i]=='';i++);if(tolower(sql[i])=='a')//增加属性(for(j=0;sql[i]!='';i++,j++)//判断add是否写错temp[j]=tolower(sql[i]);if(strcmp(temp,〃add〃)==0)(intfield_lengtf=0,flag=1;//field_lengtf列长度for(;sql[i]==，，;i++);for(j=0;sql[i]!=，，;i++,j++)//提取添加的列名field_name[j]=sql[i];field_name[j]=，\0，;for(;sql[i]==，，;i++);for(j=0;sql[i]!=，，&&sql[i]!二，;，;i++,j++)//提取列数据类型f_type[j]=tolower(sql[i]);f_type[j]=，\0，;for(j=0;j<5;j++)(if(strcmp(f_type,type[j])==0)(T=Type1[j];break;}}if(j==5)//列数据类型出错(error=0;memset(sql,0,sizeof(char)*300);printf("\n你输入的列数据类型有误(必须是char,int,short,float,double)，请重新输入SQL语句！\n〃)；return0;}if(T=='C')(//如果类型是char需要提取列长度,如果是int、float则固定列长度为4,double则固定列长度为8for(;sql[i]=='';i++);//提取列长度for(;sql[i]!二’’；i++)(if(sql[i]<48||sql[i]>58)//列长度必须是数字(flag=0;break;}elsefield_lengtf二field_lengtf*10+(sql[i]-48);}if(flag==0)(error=0;memset(sql,0,sizeof(char)*300);printf("\n你输入的列长度有误(必须是数字)，请重新输入SQL语句!\n");return0;if(!(f=OpenDbf()))(printf("打开文件失败!\n");return0;}}elseif(T=='N'||T=='F')field_lengtf=4;elseif(T=='D')field_lengtf=8;elseif(T=='S')field_lengtf=2;for(;sql[i]=='';i++);for(j=0;sql[i]!二’’&&sql[i]!=';';i++,j++)condition[j]=tolower(sql[i]);condition[j]='\0';if(condition[0]!=';'&&condition[0]!='\0')(if(strcmp(condition,"primary")==0)//判断是否为主键(for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=';';i++,j++)temp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,〃key〃)==0)con[0].flag=1;else(error=0;printf("\n你输入的'KEY'有误，请重新输入SQL语句！\n");}}elseif(strcmp(condition,〃unique〃)==0)//判断列是否取唯一值con[0].flag=2;elseif(strcmp(condition,"not")==0)//判断是否为空(for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=';';i++,j++)condition[j]=tolower(sql[i]);condition[j]='\0';if(strcmp(condition,"null")==0)con[0].flag=3;else(error=0;printf("\n你输入的约束条件'NOTNULL'有误，请重新输入SQL语句!\n");}else//约束条件错误(error=0;printf("\n你输入的约束条件有误(必须PARIMARYKEY,UNIQUE,NOTNULL)，请重新输入SQL语句！\n〃)；}}if(error!=0)(AddField(f,field_name,T,field_lengtf,con[0].flag);if(!(fp=fopen("d:\\student.dat","a+b")))(printf("打开约束性条件文件失败，请重新输入SQL语句!\n");return0;}fwrite(&con,sizeof(Condition),1,fp);fclose(fp);}}elseif((strcmp(temp,"alter"))==0)//修改属性(for(;sql[i]=='';i++);for(j=0;sql[i]!=''；i++,j++)//提取columntemp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,〃column〃)！=0)//判断column是否写正确printf("\n你输入的’column'有误，请重新输入SQL语句!\n");else(for(;sql[i]=='';i++);for(j=0;sql[i]!='';i++,j++)//提取列名field_name[j]=tolower(sql[i]);field_name[j]='\0';if(GetFieldNum(f,field_name)==-1)(printf("你输入要修改的％，不存在，请重新输入SQL语句!\n",field_name);error=0;}else(num二GetFieldNum(f,field_name);for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=';';i++,j++)//提取列数据类型f_type[j]=tolower(sql[i]);f_type[j]='\0';for(j=0;j<5;j++)(if(strcmp(f_type,type[j])==0)T=Type1[j];break;}}if(j==5)//列数据类型有误(error=0;printf("\n你输入的列数据类型有误(必须是char,int,short,float,double)，请重新输入SQL语句！\n〃)；}else(intflag=1,field_lengtf=0;if(T=='C')(〃如果类型是char需要提取列长度，如果是int、float则固定列长度为4,double则固定列长度为8for(;sql[i]=='';i++);for(;sql[i]!=''；i++)//提取列长度(if(sql[i]<48||sql[i]>58)//列长度必须是数字(flag=0;break;elsefield_lengtf二field_lengtf*10+(sql[i]-48);}if(flag==0)(error=0;printf("\n你输入的列长度有误(必须是数字)，请重新输入SQL语句!\n");}else(if(!(f=OpenDbf()))(printf("打开文件失败!\n");return0;}}}elseif(T=='N'||T=='F')field_lengtf=4;elseif(T=='D')field_lengtf=8;elseif(T=='S')field_lengtf=2;AlterField(f,field_name,T,field_lengtf,0);}}}else(error=0;printf("你输入的SQL语句有错误，请重新输入!\n");}}elseif(tolower(sql[i])=='d')//删除属性(for(j=0;sql[i]!='';i++,j++)//提取droptemp[j]=tolower(sql[i]);temp[j]='\0';if(strcmp(temp,"drop")!=0)//判断drop是否写正确(error=0;printf("\n你输入的约束条件'DROP'有误，请重新输入SQL语句!\n");}else//drop正确(for(;sql[i]=='';i++);for(j=0;sql[i]!=''&&sql[i]!=';';i++,j++)field_name[j]=tolower(sql[i]);field_name[j]='\0';if(GetFieldNum(f,field_name)==-1)//判断该列是否存在(printf("你输入要删除的％，不存在，请重新输入SQL语句!\n",field_name);error=0;}else(if((!(fp=fopen(〃d:\\student.dat〃，〃r+b〃))))(printf("打开约束性条件文件失败，请重新输入SQL语句!\n");return0;}fread(&con,sizeof(Condition)*f->rec.realCounts,1,fp);num二GetFieldNum(f,field_name);for(;num<f->rec.realCounts;num++)//将此列以后的列提前一列con[num]=con[num+1];fp二fopen(〃d:\\student.dat〃，〃w+b〃)；fwrite(&con,sizeof(Condition)*f->rec.realCounts,1,fp);fclose(fp);f->rec.realCounts--;DropField(f,field_name,f->rec.realCounts);}else(error=0;printf("\n你输入的alter类型有误(add,altercolumn,drop)，请重新输入、。1语句!\n〃)；}}}}if(error==0)〃出错(memset(sql,0,sizeof(char)*300);return0;}return1;}intOutPut()(inti;pDbfHandf;//pDbfRec*rec;FILE*fp;Conditioncon[MAX];if(!(f=OpenDbf()))(printf("打开文件失败!\n");return0;}if(fp=fopen("d:\\student.dat","r+b"))(fread(&con,sizeof(Condition)*f->rec.realCounts,1,fp);printf(〃 +〃)；for(i=0;i<f->rec.realCounts;i++)printf(〃 +");printf(〃\n〃)；printf(〃属性名|〃)；for(i=0;i<f->rec.realCounts;i++)(if(f->rec.field[i].fieldName!二NULL)printf(〃％-6s|〃,f->rec.field[i].fieldName);}printf(〃\n〃)；printf(〃 +〃)；for(i=0;i<f->rec.realCounts;i++)printf(〃 +〃)；printf(〃\n〃)；printf(〃完整性约束|〃)；for(i=0;i<f->rec.realCounts;i++)switch(con[i].flag)(case1:printf("主键|");break;case2:printf("唯一值|");break;case3:printf("非空|");break;default:printf("|");}}printf(〃\n〃)；printf(〃 +〃)；for(i=0;i<f->rec.realCounts;i++)printf(〃 +");printf(〃\n〃)；printf(〃TYPE|〃)；for(i=0;i<f->rec.realCounts;i++)(switch(f->rec.field[i].fieldType)case'N':printf("int|");break;caseC:printf("char|");break;caseS:printf("short|");break;caseF:printf("float|");break;case'D':printf("double|");break;default:printf("|");}}printf(〃\n〃)；printf(〃 +〃)；for(i=0;i<f->rec.realCounts;i++)printf(〃 +");printf(〃\n〃)；printf(〃LENGTH|〃)；for(i=0;i<f->rec.realCounts;i++)printf("%2d|”,f->rec.field[i].fiel