CRUD Operationen

1 files changed, 104 insertions, 44 deletions

diff --git a/src/db-test.c b/src/db-test.c
index 439ed79..1538702 100644
--- a/src/db-test.c
+++ b/src/db-test.c
@@ -1,9 +1,13 @@
+#include <fcntl.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <limits.h>
+#include <string.h>
 
+// Berkeley DB 1.85
 #include <db.h>
-#include <fcntl.h>
+
+#define MODE 0600
 
 #define USERNAME_LENGTH 20
 #define FULLNAME_LENGTH 50
@@ -11,60 +15,116 @@
 typedef struct {
         char username[USERNAME_LENGTH];
         char fullname[FULLNAME_LENGTH];
-        int age;
+        int  age;
 } user_type;
 
-int main(void)
+void
+insert(DB *database)
 {
-        DB *db = dbopen("./database.db", O_RDWR | O_CREAT, 0644, DB_BTREE, NULL); // NOLINT
-        if ( db != NULL ) {
-                (void) fprintf(stderr, "Datenbank eröffnet...\n");
+        user_type users[] = {
+                { "datengott", "Thomas Schmucker", 44 },
+                { "user1", "Sabine Müller", 23 },
+                { "sql-user", "SQL Database User", -1 }
+        };
 
-#if INSERT
-                user_type users[] = {
-                        { "datengott", "Thomas Schmucker", 44 },
-                        { "user1", "Sabine Müller", 23 },
-                        { "sql-user", "SQL Database User", -1 }
-                };
+        for ( int i = 0; i != 3; ++i ) {
+                DBT data = { .data = &users[i], .size = sizeof(users[i]) };
+                DBT key  = { .data = users[i].username, .size = strlen(users[i].username) };
 
-                for ( int i = 0; i != 3; ++i ) {
-                        DBT data = { .data = &users[i], .size = sizeof(users[i]) };
-                        DBT key = { .data = &users[i].username, .size = sizeof(users[i].username) };
-
-                        int res = db->put(db, &key, &data, 0);
-                        if ( res == -1 ) {
-                                fprintf(stderr, "failed to insert data!\n");
-                        }
+                int res = database->put(database, &key, &data, 0);
+                if ( res == -1 ) {
+                        (void) fprintf(stderr, "failed to insert data!\n");
                 }
-#endif
+        }
+}
 
-#if LOOKUP
-                {
-                        DBT key = { .data = &users[0].username, .size = sizeof(users[0].username) };
-                        DBT data;
+void
+update(DB *database, const char *username, int new_age)
+{
+        DBT key = { .data = (void *) username, .size = strlen(username) };
+        DBT old_data;
 
-                        int res = db->get(db, &key, &data, 0);
-                        if ( res == 0 ) {
-                                user_type *user = data.data;
-                                printf("Fullname: %s, Age: %d\n", user->fullname, user->age);
-                        }
-                }
-#endif
+        int res = database->get(database, &key, &old_data, 0);
+        if ( res != 0 ) {
+                (void) fprintf(stderr, "update: Datensatz %s nicht gefunden!\n", username);
+                return;
+        }
 
-                {
-                        DBT key;
-                        DBT data;
+        // update
+        user_type user;
+        memcpy(&user, old_data.data, sizeof user);
+        user.age = new_age;
 
-                        int err = db->seq(db, &key, &data, R_FIRST);
-                        while ( !err ) {
-                                user_type *user = data.data;
-                                printf("Fullname: %s, Age: %d\n", user->fullname, user->age);
+        DBT new_data = {
+                .data = &user,
+                .size = sizeof user
+        };
 
-                                err = db->seq(db, &key, &data, R_NEXT);
-                        }
-                }
+        res = database->put(database, &key, &new_data, 0);
+
+        if ( res != 0 ) {
+                (void) fprintf(stderr, "update: Datensatz %s wurde nicht aktualisiert\n", username);
+        }
+}
 
-                db->close(db);
+void delete(DB *database, const char *username)
+{
+        DBT key = { .data = (void *) username, .size = strlen(username) };
+
+        int res = database->del(database, &key, 0);
+        if ( res != 0 ) {
+                (void) fprintf(stderr, "update: Datensatz %s wurde nicht gelöscht\n", username);
         }
+}
+
+void
+lookup(DB *database, const char *username)
+{
+        DBT key = { .data = (void *) username, .size = strlen(username) };
+        DBT data;
+
+        int res = database->get(database, &key, &data, 0);
+        if ( res == 0 ) {
+                user_type *user = data.data;
+                printf("%.*s -> %s (%d)\n", (int) key.size, (char *) key.data, user->fullname, user->age);
+        }
+}
+
+void
+list(DB *database)
+{
+        DBT key;
+        DBT data;
+
+        int err = database->seq(database, &key, &data, R_FIRST);
+        while ( !err ) {
+                user_type *user = data.data;
+                printf("%.*s -> %s (%d)\n", (int) key.size, (char *) key.data, user->fullname, user->age);
+
+                err = database->seq(database, &key, &data, R_NEXT);
+        }
+}
+
+int
+main(void)
+{
+        DB *database = dbopen("./database.db", O_RDWR | O_CREAT, MODE, DB_BTREE, NULL);
+        if ( database == NULL ) {
+                (void) fprintf(stderr, "Datenbank konnte nicht geöffnet werden\n");
+                return EXIT_FAILURE;
+        }
+
+        insert(database);
+
+        lookup(database, "user1");
+
+        delete(database, "user1");
+
+        update(database, "datengott", 50);
+
+        list(database);
+
+        database->close(database);
+
         return EXIT_SUCCESS;
 }