A34iunxM

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