This code implements a simple text-based database management program in...

September 3, 2025 at 10:53 PM

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define DataBase "TEST/database.txt"

// Funzione per aggiungere un record alla base di dati
void aggiungiRecord() {
  char chiave[255], valore[255], record[512];
  
  // Prendo in input la chaive e il valore da aggiungere alla base di dati
  printf("Inserisci chiave: ");
  fgets(chiave, sizeof(chiave), stdin);
  chiave[strcspn(chiave, "\n")] = 0;

  printf("Inserisci valore: ");
  fgets(valore, sizeof(valore), stdin);
  valore[strcspn(valore, "\n")] = 0;
  // COncateno la chiave al valore separandoli con un :
  snprintf(record, sizeof(record), "%s:%s\n", chiave, valore);
  
  // Accedo al file e concateno la nuova riga alla fine del file
  FILE *file = fopen(DataBase, "a");
  if (file) {
    fputs(record, file);
    fclose(file);
    printf("Record aggiunto.\n");
  } else {
    perror("Errore apertura database");
  }
}

// Funzione per settaciare una base di dati per dato una chiave
void cercaRecord() {
  char chiave[64], riga[512];
  // Prendo in input la chaive da cercare
  printf("Chiave da cercare: ");
  fgets(chiave, sizeof(chiave), stdin);
  chiave[strcspn(chiave, "\n")] = 0;
  
  // Accedo al file data base
  FILE *file = fopen(DataBase, "r");
  if (!file) {
    perror("Errore apertura database");
    return;
  }
  
  // Controllo riga per riga se la chiave e presente all'interno della base di dati
  int trovato = 0;
  while (fgets(riga, sizeof(riga), file)) {
    if (strstr(riga, chiave)) {
      fputs(riga, stdout);
      trovato = 1;
    }
  }
  
  if (!trovato)
    printf("Nessun record trovato.\n");

  fclose(file);
}

// Comparator per qsort
int comp(const void *a, const void *b) {
  const char *pa = *(const char **)a;
  const char *pb = *(const char **)b;
  return strcmp(pa, pb);
}

// Funzione per ordinare la base di dati
void ordinaDatabase() {
  // Accedo alla base di dati in modalita lettura
  FILE *file = fopen(DataBase, "r");
  if (!file) {
    perror("Errore apertura database");
    return;
  }

  char *righe[2048];
  int count = 0;
  char buffer[2048];
  // Salvo il contenuto del file nel buffer
  while (fgets(buffer, sizeof(buffer), file) && count < 2048) {
    // Duplico le righe salvate nel buffe in righe
    righe[count] = strdup(buffer);
    if (!righe[count]) {
      perror("malloc fallita");
      fclose(file);
      return;
    }
    count++;
  }
  fclose(file);
  
  // Funzione per il sorting delle righe
  qsort(righe, count, sizeof(char *), comp);
  
  // Apro il file in modalita scrittura
  file = fopen(DataBase, "w");
  if (!file) {
    perror("Errore scrittura database");
    for (int i = 0; i < count; i++) 
      free(righe[i]);
    return;
  }
  // Riscrivo le righe riordinate nel file
  for (int i = 0; i < count; i++) {
    fputs(righe[i], file);
    free(righe[i]);
  }
  fclose(file);

  printf("Database ordinato.\n");
}

// Funzione per la stampa della base di dati
void mostraDatabase() {
  // Accedo al file
  FILE *file = fopen(DataBase, "r");
  if (!file) {
    perror("Errore apertura database");
    return;
  }
  
  // Stampo il contenuto della base di dati riga per riga
  char riga[512];
  printf("Contenuto database:\n");
  while (fgets(riga, sizeof(riga), file)) {
    fputs(riga, stdout);
  }
  fclose(file);
}

int main() {
  int scelta;
  // In caso la base di dati non ci sia ancora lo creo
  FILE *file = fopen(DataBase, "a"); 
  if (file) 
    fclose(file);
  // Menu persistente per l'interazione utente programma
  do {
    printf("\nGestore Database di Testo\n");
    printf("1) Aggiungi Record\n");
    printf("2) Cerca Record\n");
    printf("3) Ordina Base di Dati\n");
    printf("4) Mostra Base di Dati\n");
    printf("5) Esci\n");
    printf("Scelta: ");
    if (scanf("%d", &scelta) != 1) {
      while (getchar() != '\n');
        continue;
    }
    getchar(); // consuma newline

    switch (scelta) {
      case 1: 
        aggiungiRecord(); 
        break;
      case 2: 
        cercaRecord(); 
        break;
      case 3: 
        ordinaDatabase(); 
        break;
      case 4: 
        mostraDatabase(); 
        break;
      case 5: 
        printf("Chiusura.\n"); 
        break;
      default: 
        printf("Scelta non valida.\n");
    }
  } while (scelta != 5);

  return 0;
}

This code implements a simple text-based database management program in C. Let's break down its functionality and what each part of the code does:

Components of the Code:

DataBase Definition
- The database file is defined as a text file, "TEST/database.txt". Records are managed and stored in this file.
Functions:
- aggiungiRecord()
  - Prompts the user to input a key and a value.
  - Combines the key and value into a single record in the format key:value.
  - Appends the new record as a new line to the database text file.
- cercaRecord()
  - Asks the user for a key to search for in the database.
  - Opens the database file and reads it line by line.
  - Prints any record that contains the input key.
  - If the key is not found, it reports "Nessun record trovato" (No record found).
- ordinaDatabase()
  - Reads all the lines from the database into memory (up to a fixed limit of 2048 lines).
  - Uses the qsort function to sort the lines in lexical order.
  - Writes the sorted lines back to the database file, overwriting the previous contents.
  - Frees memory for the dynamically allocated lines.
- mostraDatabase()
  - Reads and displays all the contents of the database file, line by line.
Main Function:
- Implements a text-based menu system for interacting with the user.
- Options:
  1. Add a new record to the database.
  2. Search for a record by key.
  3. Sort the database alphabetically.
  4. Display all the records in the database.
  5. Exit the program.
- Ensures the database file is created if it doesn't already exist (using fopen with the "a" mode).
- Continues to display the menu until the user chooses to exit.

How the Program Works:

The program operates on a simple file-based database. Each record in the database is stored in the format:
```
key:value
```
Users can:
- Add new records to the file.
- Search for specific records containing a particular substring (key).
- Sort the database in alphabetical order based on the lines (keys and values combined).
- Display all records in the database file.

Possible Limitations:

Key Duplication: The program doesn't enforce unique keys, so the same key can be added multiple times with different values.
Memory Usage: Sorting the database requires reading all its lines into memory, which could fail or lead to high memory usage for very large databases.
Error Handling: The program does basic error checking (e.g., ensuring files can be opened), but additional checks (e.g., malformed input) might be beneficial.
Search Behavior: The search function matches any line containing the key as a substring, which might lead to unintended results if key overlaps with part of a value.

Summary:

This program is a basic implementation of a text-based database with functionalities for adding, searching, sorting, and displaying records. It uses standard C file I/O functions and manual memory management to handle database interactions. This makes it a useful tool for managing small datasets or for educational purposes to understand file-based database concepts in C.

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This code implements a simple text-based database management program in...

Components of the Code:

Functions:

Main Function:

How the Program Works:

Possible Limitations:

Summary: