fstream fin;

fin.open(data_keep_filename,ios::in);

if(!fin.is_open()) return;

string x;

Database* now_database;

Table* now_table;

while(getline(fin,x)){

auto t=cut(x);

if(t[0]=="database:"){

database[t[1]]=new Database(t[1]);

now_database=database[t[1]];

all_database.push_back(t[1]);

}

else if(t[0]=="table:"){

string tablename=t[1],prime_key=t[2];

now_database->create(tablename,prime_key);

now_table=(*now_database)[tablename];

}

else if(t[0]=="column:"){

for(int i=1;i<t.size();i+=3){

bool q;

if(t[i+2]=="1") q=true;

else q=false;

if(t[i+1][0]=='i') t[i+1]="INT";

else if(t[i+1][0]=='c') t[i+1]="CHAR";

now_table->create(t[i],t[i+1],q);

}

}

else if(t[0]=="data:"){

for(int i=1;i<t.size();++i){

(*now_table)[i-1]->insert(t[i]);

}

}

/*else if(t[0]=="nowdatabase:"){

}

fin.close();

if(result.size()<2) return;

for(int i=0;i<result[0].size();++i){

cout<<result[0][i]<<'\t';

}

cout<<endl;

for(int i=1;i<result.size();++i){

for(int j=0;j<result[i].size()-1;++j){

cout<<result[i][j]<<'\t';

}

cout<<endl;

}

if(result.size()<2) return;

for(int i=0;i<result[0].size();++i){

cout<<result[0][i]<<'\t';

}

cout<<endl;

for(int i=1;i<result.size();++i){

for(int j=0;j<result[i].size();++j){

cout<<result[i][j]<<'\t';

}

cout<<endl;

}

string todo; Database* now = NULL; //now表示现在正在使用的数据库，便于切换操作

map<string,Database*> database; //从数据库名映射至相应的数据库指针

vector<string>all_database;

//便于测试，先不从存档中读入数据

//read_data(database,all_database);

//使用该函数即可完成存档数据的读取（数据默认保存在"data_keep.txt"中，可以通过修改data_keep_filename的值来修改储存数据的文件名）

while(getline(cin,todo,';')) {

if (todo=="") continue;

getchar();

if (todo[todo.length()-1]==' ') todo.erase(todo.end()-1); //删除行末空格

todo.push_back(';');//适应之前的代码

if (str_com(todo.substr(0,8).c_str(),"CREATE D")) { //创建数据库

string dname = todo.substr(16,todo.length()-17); //截取数据库名dname，下同

database[dname] = new Database(dname);

all_database.push_back(dname);

}

else if (str_com(todo.substr(0,6),"DROP D")) { //删除数据库

string dname = todo.substr(14,todo.length()-15);

if (database.find(dname)==database.end()) { //讨论待删除的数据库不存在的情况

cout << "Database Not Found!\n";

continue;

}

int i;

for(i=0;i<all_database.size();++i){

if(all_database[i]==dname){

//all_database.erase(all_database.begin()+i);

all_database.erase(all_database.begin()+i);

break;

}

}

delete database[dname]; //释放内存

database.erase(dname);

}

else if (str_com(todo.substr(0,4),"USE ")) { //利用now指针切换数据库

string dname = todo.substr(4,todo.length()-5);

if (database.find(dname)==database.end()) {

cout << "Database Not Found!\n";

continue;

}

now = database[dname];

}

else if (str_com(todo.substr(0,6),"SHOW D")) { //打印现有数据库名

if (!database.empty()) { //没有数据库则不输出

cout << "Database\n";

for (auto t=database.begin();t!=database.end();t++) {

cout << (t->second->getname()) << endl;

}

}

}

else if (str_com(todo.substr(0,8),"CREATE T")) { //创建表格

int p = todo.find("(",13);

string tname = todo.substr(13,p-13); //截取表格名tname，下同

int q = todo.find("PRIMARY KEY",p); //寻找主键

if (q==-1) q = todo.find("primary key",p);

int s = todo.find(")",q);

string prime = todo.substr(q+12,s-q-12); //截取主键名

now->create(tname,prime); //调用成员函数建表

if (todo[s+1]==')') { //将定义主键的子串移除

if (todo[q-1]==' ') q-=2; else q--; s++;

todo.erase(todo.begin()+q,todo.begin()+s);

}

else {

if (todo[q-1]==' ') q--; s+=2;

todo.erase(todo.begin()+q,todo.begin()+s);

}

p++; bool n;

while (true) {

s = todo.find(" ",p);

string cname = todo.substr(p,s-p); //截取表头变量名cname，下同

int t = todo.find(" ",s+1);

int w = todo.find(",",s+1);

if (w==-1) w = todo.find(")",s+1);

n = true; string type;

if (t>w||t==-1) { //判断该表头变量是否not null，用布尔值n表示

type = todo.substr(s+1,w-s-1);

(*now)[tname]->create(cname,type,n); //创建表格的一列

}

else {

n = false;

type = todo.substr(s+1,t-s-1);

(*now)[tname]->create(cname,type,n);

}

p = todo.find(",",p); //继续建立下一列

if (p==-1) break;

if (todo[p+1]==' ') p += 2;

else p++;

}

}

else if (str_com(todo.substr(0,6),"DROP T")) { //删除表格

string tname = todo.substr(11,todo.length()-12);

if (!(now->find_table(tname))) { //讨论表格不存在的情况

cout << "Table Not Found!\n";

continue;

}

now->del(tname);

}

else if (str_com(todo.substr(0,6),"SHOW T")) { //展示现有数据库的表格

now->show();

}

else if (str_com(todo.substr(0,6),"SHOW c")) { //展示建表信息

string tname = todo.substr(18,todo.length()-19);

if (!(now->find_table(tname))) {

cout << "Table Not Found!\n";

continue;

}

(*now)[tname]->show_column();

}

else if (str_com(todo.substr(0,8),"INSERT I")) { //在表格中插入数据

int p = todo.find("(",0);

string tname = todo.substr(12,p-12);

if (!(now->find_table(tname))) {

cout << "Table Not Found!\n";

continue;

}

p++; int q = todo.find("(",p); q++; //用两套指针，分别截取表头变量名cname和其数值value

int pt = todo.find(")",p); int qt = todo.find(")",q);

int pp = todo.find(",",p); int qq = todo.find(",",q);

string cname,value; string to_check = todo.substr(p,pt-p); //to_check为tname(...)括号中的内容

if ((*now)[tname]->null_check(to_check)) { //检查是否有not null变量没有赋值，有则报错

cout << "Wrong Insert! Some Not Null field is not filled!\n";

continue;

}

while ((pp<pt)&&(qq<qt)&&(pp!=-1)&&(qq!=-1)) {

cname = todo.substr(p,pp-p);

value = todo.substr(q,qq-q);

if ((*now)[tname]->find_column(cname)) (*((*now)[tname]))[cname]->insert(value);

else cout << "Column " << cname << " Is Not Found! Filled As Default!\n"; //讨论所指示的表头变量名不存在的情况，此时它将用缺省值填充

if (todo[pp+1]==' ') p=pp+2; else p=pp+1;

if (todo[qq+1]==' ') q=qq+2; else q=qq+1;

pp = todo.find(",",p); qq = todo.find(",",q);

}

cname = todo.substr(p,pt-p);

value = todo.substr(q,qt-q);

if ((*now)[tname]->find_column(cname)) (*((*now)[tname]))[cname]->insert(value);

else cout << "Column " << cname << " Is Not Found! Filled As Default!\n";

(*now)[tname]->default_fill(); //对于该次赋值，如果表中有某些变量没有赋值，则调用default_fill函数用缺省值NULL填充

(*now)[tname]->sort_prime(); //根据主键给各行排序

}

else if (str_com(todo.substr(0,7),"DELETE ")) { //删除行

int p = todo.find(' ',12);

if (p==-1) p = todo.length()-1;

string tname = todo.substr(12,p-12);

if (!(now->find_table(tname))) {

cout << "Table Not Found!\n";

continue;

}

string clause; //截取whereclause

int pp = todo.find(" WHERE ");

if (pp==-1) pp = todo.find(" where ");

if (pp==-1) clause = ""; //若没有whereclause，则设为空，下同

else clause = todo.substr(pp+7,todo.length()-pp-8);

(*now)[tname]->del_row((*now)[tname]->whereClauses(clause)); //调用函数删除行

}

else if (str_com(todo.substr(0,7),"UPDATE ")) { //修改表格信息

int p = todo.find(' ',7);

string tname = todo.substr(7,p-7);

if (!(now->find_table(tname))) {

cout << "Table Not Found!\n";

continue;

}

int q = todo.find('=',p+5);

int s = todo.find(' ',p+5);

if (s==-1) s = todo.length()-1;

string clause;

int pp = todo.find(" WHERE ");

if (pp==-1) pp = todo.find(" where ");

if (pp==-1) clause = "";

else clause = todo.substr(pp+7,todo.length()-pp-8);

string cname = todo.substr(p+5,q-p-5);

string value = todo.substr(q+1,s-q-1);

(*now)[tname]->update_row(cname,value,(*now)[tname]->whereClauses(clause));

}

else{

todo.erase(todo.size()-1);

auto t=cut(todo);int l=t.size();

if (str_com(todo.substr(0,7).c_str(),"ADDTIME") || str_com(todo.substr(0,7).c_str(),"ADDDATE")) {

string s1, s2;

if(t.size() == 2){

s1 = t[0].substr(t[0].find('(') + 1);

s1 = s1.substr(0, s1.length() - 1);

s2 = t[1].substr(0, t[1].find(')'));

} else{

s1 = t[1].substr(0, t[1].length() - 1);

s2 = t[2].substr(0, t[2].find(')'));

}

clear_qua(s1);

if(str_com(todo.substr(0,7).c_str(),"ADDTIME")) cout << addtime(s1, s2) << endl;

else cout << adddate(s1, s2) << endl;

}

else if (Tolower(todo).find("outfile")!=-1){//数据导出

fstream fout;

string filename=t[l-3].substr(1,t[l-3].size()-2);

ifstream check_if_exist(filename);

if(check_if_exist.is_open()){

continue;

}

fout.open(filename,ios::out);

if(now->find_table(t[l-1])){

Table* ptable=now->get_table(t[l-1]);

if(t[1]=="*"){

//cout<<"getin";

for(int i=0;i<ptable->getrowsize();++i){

//cout<<"get";

for(int j=0;j<ptable->getsize();++j){

fout<<(*((*ptable)[j]))[i]<<"\t";

//cout<<"write";

}

fout<<endl;

}

}

else{

vector<string>columnname;

for(int i=1;i<=l-6;++i){

if(i!=l-6){

columnname.push_back(t[i].erase(t[i].size()-1));

}

else{

columnname.push_back(t[i]);

}

}

for(int i=0;i<ptable->getrowsize();++i){

for(int j=0;j<columnname.size();++j){

fout<<(*(*ptable)[columnname[j]])[i]<<"\t";

}

}

}

}

fout.close();

}

else if(Tolower(todo).find("infile")!=-1){//数据导入

string filename;

for(int i=0;i<l;++i){

if(Tolower(t[i])=="infile"){

filename=t[i+1].substr(1,t[i+1].size()-2);

break;

}

}

fstream fin;

fin.open(filename,ios::in);

if(t[l-1].back()!=')'){

string s;

Table* ptable=now->get_table(t[l-1]);

while(getline(fin,s)){

auto u=cut(s);

for(int i=0;i<u.size();++i){

(*ptable)[i]->insert(u[i]);

}

}

}

else{

string tablename="";

int i;int j;

for(i=0;i<l;++i){

if(Tolower(t[i])=="table"){

for(j=0;j<t[i+1].size();++j){

if(t[i+1][j]=='(') break;

tablename+=t[i+1][j];

}

break;

}

}

Table* ptable=now->get_table(tablename);

vector<string>columnname;

columnname.push_back(t[i+1].substr(j+1,t[i+1].size()-j-2));

for(int u=i+2;u<l;++u){

columnname.push_back(t[u].substr(0,t[u].size()-1));

}

string s;

while(getline(fin,s)){

auto u=cut(s);

for(int i=0;i<u.size();++i){

(*ptable)[columnname[i]]->insert(u[i]);

}

ptable->default_fill();

}

ptable->sort_prime();

}

fin.close();

}

else if(find_pos(t,"join",true)!=-1){//实现join功能

int pos_from=find_pos(t,"from");

vector<string>joins,alltable;

vector<vector<string>>needs;

vector<string>temp;

vector<string>nowtables;

for(int i=pos_from+1;i<l;++i){

string x=Tolower(t[i]);

if(x=="inner"||x=="left"||x=="right"){

string u=x+' ';

u+="join";++i;

joins.push_back(u);

needs.push_back(temp);

temp.clear();

}

else if(x=="join"){

string u="inner join";

joins.push_back(u);

needs.push_back(temp);

temp.clear();

}

else{

if(temp.empty()) alltable.push_back(t[i]);

temp.push_back(t[i]);

if(i==l-1) needs.push_back(temp);

}

}

vector<vector<pair<int,bool>>>r;//bool为true表示需要显示，否则为NULL

for(int i=0;i<(*now)[needs[0][0]]->getrowsize();++i){

vector<pair<int,bool>>temp;

temp.push_back(make_pair(i,true));

r.push_back(temp);

}

nowtables.push_back(needs[0][0]);

for(int i=0;i<joins.size();++i){

nowtables.push_back(needs[i+1][0]);

r=now->join_it(r,nowtables,needs[i+1],joins[i]);

}

vector<string>_columnname=get_show_columnname(t);

map<string,int>sub_table;

for(int i=0;i<alltable.size();++i) sub_table[alltable[i]]=i;

vector<vector<string>>result;result.push_back(clear_tablename(_columnname));

for(int i=0;i<r.size();++i){

vector<string>temp;

for(int j=0;j<_columnname.size();++j){

int u=_columnname[j].find(".");

string x=_columnname[j].substr(0,u);

string y=_columnname[j].substr(u+1,_columnname[j].size()-u-1);

int o=sub_table[x];

string str="NULL";

if(r[i][o].second){

str=(*(*(*now)[x])[y])[r[i][o].first];

}

temp.push_back(str);

}

result.push_back(temp);

}

print_result_norows(result);

}

else if(Tolower(todo).find("union")!=-1){//实现union操作符

//先实现UNION连接两个结果集，有需要再改进(已实现连接多个结果集)

//之前组只实现了select之后有一个属性，这里已改进为可以有多个属性（单表）

auto columnname=get_show_columnname(t);

vector<string>selects,unions;int last_pos=0;

int pos_order=find_pos(t,"order");

string ordername="";

vector<vector<vector<string>>>results;

for(int i=0;i<l;++i){

if(Tolower(t[i])=="union"){

selects.push_back(putvector_tostring(t,last_pos,i-1));

if(Tolower(t[i+1])=="all"){

unions.push_back("union all");

last_pos=i+2;++i;

}

else{

unions.push_back("union");

last_pos=i+1;

}

}

else if(Tolower(t[i])=="order"){

selects.push_back(putvector_tostring(t,last_pos,i-1));

ordername=t[i+2];break;

}

if(i==l-1){

selects.push_back(putvector_tostring(t,last_pos,i));

}

}

for(int i=0;i<selects.size();++i){

results.push_back(now->multiple_select(selects[i]));

}

vector<vector<string>>result=results[0];

int pos_start;//在unions中"union"第一次出现的位置

for(pos_start=unions.size()-1;pos_start>=0;pos_start--){

if(unions[pos_start]=="union") break;

}

for(int i=0;i<=pos_start;++i){

result=(*now)[0]->combine(columnname,result,results[i+1],1);

}

for(int i=pos_start+1;i<unions.size();++i){

result=(*now)[0]->combine(columnname,result,results[i+1],0);

}

result.insert(result.begin(),columnname);

auto final_result=result;

if(pos_order!=-1){

final_result=(*now)[0]->orderit(result,ordername);

}

print_result(final_result);

}

else if(Tolower(todo).find("order by")!=-1){//排序语句

Table* ptable;

int i;//i对应from出现的下标

for(i=0;i<t.size();++i){

if(Tolower(t[i])=="from"){

ptable=now->get_table(t[i+1]);

break;

}

}

int pos_group,pos_order;//记录order和group在t中的下标

pos_group=find_pos(t,"group");

pos_order=find_pos(t,"order");

string todo="";

for(int i=0;i<(pos_group==-1?pos_order:pos_group);++i){

if(!i) todo+=t[i];

else{

todo+=' ';todo+=t[i];

}

}

auto need_group=now->multiple_select(todo);

auto columnname=get_show_columnname(t);

need_group.insert(need_group.begin(),columnname);

vector<vector<string>>need_order;

if(pos_group!=-1){

vector<string>group;

for(int i=pos_group+2;i<pos_order;++i){

group.push_back(getvalid_string(t[i]));

}

need_order=ptable->groupit(need_group,group);

}

else{

need_order=need_group;

}

string order=t[pos_order+2];

auto result=ptable->orderit(need_order,order);

print_result(result);

}

else if(Tolower(todo).find("group by")!=-1){//分组语句

Table* ptable=nullptr;

int i;//i对应from出现的下标

for(i=0;i<t.size();++i){

if(Tolower(t[i])=="from"){

ptable=now->get_table(t[i+1]);

break;

}

}

if(ptable==nullptr) continue;

int pos_group=find_pos(t,"group");//记录group在t中的下标

string todo="";

for(int i=0;i<pos_group;++i){

if(!i) todo+=t[i];

else{

todo+=' ';todo+=t[i];

}

}

auto need_group=now->multiple_select(todo);

auto columnname=get_show_columnname(t);

need_group.insert(need_group.begin(),columnname);

vector<string>group;

for(int i=pos_group+2;i<l;++i){

group.push_back(getvalid_string(t[i]));

}

auto result=ptable->groupit(need_group,group);

print_result(result);

}

else if(Tolower(todo).find("count")!=-1 || Tolower(todo).find("sum")!=-1 || Tolower(todo).find("max")!=-1

|| Tolower(todo).find("min")!=-1 || Tolower(todo).find("ave")!=-1 || Tolower(todo).find("var_samp")!=-1){//实现聚合函数

Table* ptable=nullptr;

int i;//i对应from出现的下标

for(i=0;i<t.size();++i){

if(Tolower(t[i])=="from"){

ptable=now->get_table(t[i+1]);

break;

}

}

if(ptable==nullptr) continue;

string todo="";

for(int i=0;i<t.size();++i){

if(!i) todo+=t[i];

else{

todo+=' ';todo+=t[i];

}

}

auto need_group=now->multiple_select(todo);

auto columnname=get_show_columnname(t);

need_group.insert(need_group.begin(),columnname);

vector<string>group;

auto result=ptable->groupit(need_group,group);

print_result(result);

}

else if(Tolower(t[0])=="select"){//查询表格信息,包括单表和多表

int pos_from=0,pos_where=0;

for(int i=0;i<l;++i){

if(Tolower(t[i])=="from") pos_from=i;

if(Tolower(t[i])=="where") {

pos_where=i;break;

}

}

if(pos_where-pos_from>2||(!pos_where&&pos_from<l-2)){//多表

vector<string>tablename;//存储from后面的表名

int pos_from=0,pos_where=0;

for(int i=0;i<l;++i){

if(Tolower(t[i])=="from"){

pos_from=i;

}

if(Tolower(t[i])=="where"){

pos_where=i;

break;

}

}

string condition;

if(pos_where){

for(int i=pos_from+1;i<pos_where;++i){

if(i==pos_where-1){

tablename.push_back(t[i]);

}

else{

tablename.push_back(t[i].substr(0,t[i].size()-1));

}

}

int u=todo.find(" WHERE ");

if(u==-1) u=todo.find(" where ");

condition=todo.substr(u+7,todo.size()-u-7);

}

else{

condition="*";

}

vector<string>columnname;

vector<string>ctablename;//存储输出时每个列对应的表格的名字

map<string,int>table_sub;//存储输出时的表名在v中的vector中的第几个

for(int i=0;i<tablename.size();++i){

table_sub[tablename[i]]=i;

}

for(int i=1;i<pos_from;++i){

int x=t[i].find('.');

ctablename.push_back(t[i].substr(0,x));

if(i==pos_from-1){

columnname.push_back(t[i].substr(x+1,t[i].size()-x-1));

}

else{

columnname.push_back(t[i].substr(x+1,t[i].size()-x-2));

}

}

vector<vector<int>>v=now->where_multiple(tablename,condition);

if(!v.empty()){

for(int i=0;i<columnname.size();++i){

cout<<columnname[i]<<'\t';

}

cout<<endl;

}

for(int i=0;i<v.size();++i){

for(int j=0;j<columnname.size();++j){

int x=table_sub[ctablename[j]];

cout<<(*(*(*now)[ctablename[j]])[columnname[j]])[v[i][x]]<<'\t';

}

cout<<endl;

}

}

else{//单表

vector<string>columnname;

if(t[1]!="*"){

for(int i=1;i<pos_from;++i){

columnname.push_back(getvalid_string(t[i]));

}

}

else{

string tablename=t[pos_from+1];

for(int i=0;i<(*now)[tablename]->getsize();++i){

columnname.push_back((*((*now)[tablename]))[i]->getname());

}

}

auto u=now->multiple_select(todo);

u.insert(u.begin(),columnname);

print_result(u);

}

}

}

fstream fout;

fout.open(data_keep_filename,ios::out|ios::ate);

for(int i=0;i<all_database.size();++i){

database[all_database[i]]->keep_data(data_keep_filename,fout);

}

//fout<<"nowdatabase: "<<now->getname()<<endl;

fout.close();

//将数据储存

}

return 0;