92j1yvWi

1#include <bits/stdc++.h>
2using namespace std;
3
4struct node
5{
6    int data;
7    string val="";
8    int type;
9};
10
11struct cols
12{
13    string name;
14    int size;
15    int type = 0;
16    bool notNull = false;
17    bool pk = false;
18    bool unique = false;
19    string def_s = "";
20    int def_i;
21};
22
23vector<vector<vector<node *>>> db;
24vector<vector<cols *>> col;
25vector<string>table;
26node *newNode(int n)
27{
28    node *temp = new node;
29    temp->data = n;
30    temp->type = 0;
31    return temp;
32}
33
34node *newNode(string s)
35{
36    node *temp = new node;
37    temp->val = s;
38    temp->type = 1;
39    return temp;
40}
41vector <int> RELOP(vector<string>tokens,int table_id, int &i){
42    vector<cols *> ptable = col[table_id];
43    vector<int> result;
44    
45    vector<vector<node *>> rt = db[table_id];
46    for (int j = 0; j < ptable.size(); j++)
47            {
48                if (ptable[j]->name == tokens[i])
49                {
50                    i++;
51                    string op=tokens[i];
52                    i++;
53                        
54                    string curr_tok = tokens[i];
55                    if (curr_tok[0] >= '0' && curr_tok[0] <= '9'){
56                        for (int k = 0; k < rt.size(); k++)
57                        {
58                            if (op=="="){
59                                 if (rt[k][j]->data == stoi(curr_tok)) result.push_back(k);}
60                            else if (op==">"){
61                                 if (rt[k][j]->data > stoi(curr_tok)) result.push_back(k);}
62                            else if (op=="<"){
63                                 if (rt[k][j]->data < stoi(curr_tok)) result.push_back(k);}
64                            else if (op==">="){
65                                 if (rt[k][j]->data >= stoi(curr_tok)) result.push_back(k);}
66                            else if (op=="<="){
67                                 if (rt[k][j]->data <= stoi(curr_tok)) result.push_back(k);}
68                            else if (op=="!="){
69                                 if (rt[k][j]->data != stoi(curr_tok)) result.push_back(k);}
70                        }
71                        break;
72                        
73                    }
74                    else{
75                        curr_tok = curr_tok.substr(1, curr_tok.length() - 2);
76                        for (int k = 0; k < rt.size(); k++)
77                        {
78                            if (rt[k][j]->val == curr_tok) 
79                                result.push_back(k);
80                        }
81                        break;
82                    }
83
84                /*   if (tokens[i][0] == '\"' || tokens[i][0] == '\'')
85                        tokens[i] = tokens[i].substr(1, tokens[i].length() - 2);
86                    for (int k = 0; k < rt.size(); k++)
87                    {
88                        if (rt[k][j]->val == tokens[i]) 
89                            result.push_back(k);
90                    }
91                    break;*/
92                }
93            }
94            return result;
95}
96vector<int> where(vector<string> tokens, int table, int ptr)
97{
98    vector<int> result;
99    vector<cols *> ptable = col[table];
100    vector<vector<node *>> rt = db[table];
101    for (int i = ptr; i < tokens.size(); i++)
102    {
103        string s = tokens[i];
104
105        if (s == "or")
106        {
107            
108            /*i++;
109            for (int j = 0; j < ptable.size(); j++)
110            {
111                if (ptable[j]->name == s)
112                {
113                    i++;
114                    i++;
115                    if (tokens[i][0] == '\"' || tokens[i][0] == '\'')
116                        tokens[i] = tokens[i].substr(1, tokens[i].length() - 2);
117                    for (int k = 0; k < rt.size(); k++)
118                    {
119
120                        if (rt[k][j]->val == tokens[i])
121                            result.push_back(k); //same values will insert 2 times
122                    }
123                    break;
124                }
125            }*/
126        }
127        else if (s == "and")
128        {
129            i++;
130            for (int j = 0; j < ptable.size(); j++)
131            {
132                if (ptable[j]->name == s)
133                {
134                    i++;
135                    i++;
136                    if (tokens[i][0] == '\"' || tokens[i][0] == '\'')
137                        tokens[i] = tokens[i].substr(1, tokens[i].length() - 2);
138                    for (int k = 0; k < result.size(); k++)
139                    {
140                        if (rt[result[k]][j]->val != tokens[i])
141                        {
142                            result.erase(result.begin() + k);
143                            k--;
144                        }
145                    }
146                    break;
147                }
148            }
149        }
150        else if (s == ",")
151        {
152            continue;
153        }
154        else
155        {
156            result=RELOP(tokens, table,  i);
157            break;
158        }
159    }
160    return result;
161}
162/*class Dbn
163{
164    vector<tab> v;
165  public:
166    void drop(tab);
167    vector<cols *> create(vector<string>);
168    void showtables();
169};*/
170
171void print(int tb_id, vector<int> rcid)
172{
173    int i;
174    if(tb_id==-1) return;
175    for (i = 0; i < rcid.size(); i++)
176    {
177        if (rcid[i] == -1)
178            break;
179    }
180    for (int p = 0; p < rcid.size() - (i + 1); p++)
181        cout << "---------------------";
182    cout << endl;
183    for (int k = i + 1; k < rcid.size(); k++)
184    {
185        printf("| %-19s", col[tb_id][rcid[k]]->name.c_str());
186    }
187    cout << "|" << endl;
188    for (int p = 0; p < rcid.size() - (i + 1); p++)
189        cout << "---------------------";
190    cout << endl;
191    for (int j = 0; j < i; j++)
192    {
193        for (int k = i + 1; k < rcid.size(); k++)
194        {
195            if (db[tb_id][rcid[j]][rcid[k]]->val != "")
196                printf("| %-19s", db[tb_id][rcid[j]][rcid[k]]->val.c_str());
197            else
198                printf("| %-19d", db[tb_id][rcid[j]][rcid[k]]->data);
199        }
200        cout << "|" << endl;
201    }
202    for (int p = 0; p < rcid.size() - (i + 1); p++)
203        cout << "---------------------";
204    cout << endl;
205}
206
207int find_tab_id(string s){
208    for (int i = 0; i < table.size(); i++){
209        if (table[i] == s)
210            return i;
211    }
212    return -1;
213}
214int get_col_id(int tab_id,string s){
215    for (int i = 0; i < col[tab_id].size(); i++){
216        if(col[tab_id][i]->name==s) return i;
217    }
218    return -1;
219}
220void create(vector<string> tokens)
221{
222    if (find_tab_id(tokens[2]) != -1)
223    {
224        cout << "ERROR:Table " << tokens[2] << " already exists in database.\n";
225        return;
226    }
227    table.push_back(tokens[2]);
228    int j;
229    vector<cols *> tmp;
230    for (int i = 4; i < tokens.size() - 1; i++)
231    {
232        cols *temp = new cols();
233        for (j = i; tokens[j] != "," && j < tokens.size() - 1; j++)
234        {
235            if (tokens[j] == "not" && tokens[j + 1] == "null")
236            {
237                temp->notNull = true;
238                j++;
239            }
240            else if (tokens[j] == "unique")
241                temp->unique = true;
242            else if (tokens[j] == "primary" && tokens[j + 1] == "key")
243            {
244                temp->pk = true;
245                j++;
246            }
247            else if (tokens[j] == "default")
248            {
249                if (tokens[j + 2][0] == '0')
250                    temp->def_i = stoi(tokens[j + 2]);
251                else
252                    temp->def_s = tokens[j + 2];
253                j += 2;
254            }
255            else if (tokens[j] == "varchar")
256            {
257                temp->type = 1;
258            }
259            else if (tokens[j] == "int")
260            {
261                temp->type = 0;
262            }
263            else if (tokens[j] == "(")
264            {
265                temp->size = stoi(tokens[j + 1]);
266                j += 2;
267            }
268            else
269            {
270                temp->name = tokens[j];
271            }
272        }
273        i = j;
274        tmp.push_back(temp);
275    }
276    col.push_back(tmp);
277}
278 
279
280
281vector<int> select(vector<string> tokens, int &tab_id, int ptr) {
282    int i;
283    vector<int> result;
284    for( i=ptr;i<tokens.size();i++){
285        if(tokens[i]=="from") break;
286    }
287    if (i==tokens.size() || i+1==tokens.size()) {
288        cout<<"ERROR: INVALID SYNTAX\n";
289        return result;}
290    tab_id = find_tab_id(tokens[i+1]);
291    if (tab_id == -1)    {
292        cout << "ERROR:Table doesn't exist in database\n";
293    }
294    else{
295        if(i+2!=tokens.size()){
296            //if(tokens[i+2]!="where") printf("ERROR: where not found");
297            vector <int> rowids= where(tokens,tab_id,i+3);
298            for(int j=0;j<rowids.size();j++) result.push_back(rowids[j]);
299            result.push_back(-1);
300        }
301        else{
302            for(int j=0;j<db[tab_id].size();j++) result.push_back(j);
303            result.push_back(-1);
304        }
305        if(tokens[1]=="*"){
306            for(int j=0;j<db[tab_id][0].size();j++){
307                result.push_back(j);
308            }
309        }
310        else {
311            for(int j=1;j<i; j=j+2){
312                int r=get_col_id(tab_id, tokens[j]);
313                result.push_back(r);
314            }
315        }
316
317    }
318    return result;
319}
320void insert(vector<string> tokens)
321{
322    int tab_id = find_tab_id(tokens[2]);
323    if (tab_id == -1)
324    {
325        cout << "ERROR:Table doesn't exist in database\n";
326    }
327    else
328    {
329        vector<vector<node *>> curr;
330        vector<node *> tmp;
331        for (int i = 5; i < tokens.size() - 1; i += 2)
332        {
333            string curr_tok = tokens[i];
334            if (curr_tok[0] >= '0' && curr_tok[0] <= '9')
335            {
336                node *temp = newNode(stoi(curr_tok));
337                tmp.push_back(temp);
338            }
339            else
340            {
341                node *temp = newNode(curr_tok.substr(1, curr_tok.length() - 2));
342                tmp.push_back(temp);
343            }
344        }
345        if (table.size() == db.size())
346            db[tab_id].push_back(tmp);
347        else
348        {
349            curr.push_back(tmp);
350            db.push_back(curr);
351        }
352    }
353}
354
355vector<cols *> del(vector<string> tokens) {}
356
357
358
359int main()
360{
361    string s;
362
363    table.push_back("students");
364    cols* col1=new cols();
365    col1->name="rollno";
366    cols* col2=new cols();
367    col2->name="name";
368    vector <cols*> temp;
369    temp.push_back(col1);temp.push_back(col2);
370    col.push_back(temp);
371    node* s1name=new node();
372    s1name->val="Pranav";
373    node* s1roll=new node();
374    s1roll->data=1;
375    node* s2name=new node();
376    s2name->val="Ayush";
377    node* s2roll=new node();
378    s2roll->data=2;
379    vector<node*> student1;
380    student1.push_back(s1roll);student1.push_back(s1name);
381
382    vector<node*> student2;
383    student2.push_back(s2roll);student2.push_back(s2name);
384
385    vector<vector<node*>> students;
386    students.push_back(student1);
387    students.push_back(student2);
388
389
390    db.push_back(students);
391    
392    vector<int> rcid;
393    rcid.push_back(0);
394    rcid.push_back(1);
395    rcid.push_back(-1);
396    rcid.push_back(0);
397    rcid.push_back(1);
398
399    printf(">> ");
400    getline(cin, s, ';');
401    while (s != "exit")
402    {
403        stringstream check1(s);
404        string intermediate;
405        vector<string> tokens;
406        while (getline(check1, intermediate, ' '))
407            tokens.push_back(intermediate);
408        if (tokens[0] == "create")
409            create(tokens);
410        if (tokens[0] == "select"){
411            int tab_id=-1;
412            vector <int> result=select(tokens,tab_id,0);
413            print(tab_id,result);
414        }
415        if (tokens[0] == "insert")
416            insert(tokens);
417        if (tokens[0] == "delete")
418            del(tokens);
419        
420        getline(cin, s);
421        printf(">> ");
422        getline(cin, s, ';');
423    }
424    return 0;
425}