iPhone上のオブジェクトのデータベースリレーションシップをSqliteで管理するには

Question

たとえば、すべてのムービーとGenreを含むUITableViewを表示できるかどうか。ムービーの[編集]をクリックすると、新しいビューが読み込まれます（これは正しいですか、編集ビューを読み込むのですか？）。テキストボックスとセレクタのある種の並べ替え、または別のビューでジャンルを選択します。ジャンルを選択すると、ムービーテーブルに保存するGenreIdをキャプチャするにはどうすればよいですか？

CREATE TABLE movie(pk INTEGER PRIMARY KEY, title TEXT, genreId INTEGER); 

INSERT INTO make(title) VALUES('GoldFinger', 1); 
INSERT INTO make(title) VALUES('Octopussy', 1); 
INSERT INTO make(title) VALUES('Love Story', 3); 
INSERT INTO make(title) VALUES('Where Eagles Dare', 1); 
INSERT INTO make(title) VALUES('Zombies', 2); 

CREATE TABLE genre(pk INTEGER PRIMARY KEY, title TEXT); 

INSERT INTO genre(title) VALUES('Thriller'); 
INSERT INTO genre(title) VALUES('Horror'); 
INSERT INTO genre(title) VALUES('Romance'); 

私はガイドとしてSqlitebooksサンプルを使用しています。

// Movie.h 
@interface Movie : NSObject { 
// Opaque reference to the underlying database. 
sqlite3 *database; 
// Primary key in the database. 
NSInteger primaryKey; 
// Attributes. 
NSString *title; 
NSInteger *genreKey; 
// Internal state variables. Hydrated tracks whether attribute data is in the object or the database. 
BOOL hydrated; 
// Dirty tracks whether there are in-memory changes to data which have no been written to the database. 
BOOL dirty; 
NSData *data; 
} 
// Property exposure for primary key and other attributes. The primary key is 'assign'  because it is not an object, 
// nonatomic because there is no need for concurrent access, and readonly because it  cannot be changed without 
// corrupting the database. 
@property (assign, nonatomic, readonly) NSInteger primaryKey; 
// The remaining attributes are copied rather than retained because they are value  objects. 
@property (copy, nonatomic) NSString *title; 
@property (copy, nonatomic) NSInteger *genreKey; 
// Finalize (delete) all of the SQLite compiled queries. 
+ (void)finalizeStatements; 
// Creates the object with primary key and title is brought into memory. 
- (id)initWithPrimaryKey:(NSInteger)pk database:(sqlite3 *)db; 
// Inserts the book into the database and stores its primary key. 
- (void)insertIntoDatabase:(sqlite3 *)database; 
// Brings the rest of the object data into memory. If already in memory, no action is  taken (harmless no-op). 
- (void)hydrate; 
// Flushes all but the primary key and title out to the database. 
- (void)dehydrate; 
// Remove the book complete from the database. In memory deletion to follow... 
- (void)deleteFromDatabase; 

// Movie.m 
// Flushes all but the primary key and title out to the database. 
- (void)dehydrate { 
    if (dirty) { 
    // Write any changes to the database. 
    // First, if needed, compile the dehydrate query. 
    if (dehydrate_statement == nil) { 
     const char *sql = "UPDATE movie SET title=?, genreid=? WHERE pk=?"; 
     if (sqlite3_prepare_v2(database, sql, -1, &dehydrate_statement, NULL) != SQLITE_OK) { 
      NSAssert1(0, @"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(database)); 
     } 
    } 
    // Bind the query variables. 
    sqlite3_bind_text(dehydrate_statement, 1, [title UTF8String], -1, SQLITE_TRANSIENT); 
    sqlite3_bind_text(dehydrate_statement, 2, [genreId UTF8String], -1, SQLITE_TRANSIENT); 
    sqlite3_bind_int(dehydrate_statement, 3, primaryKey); 
    // Execute the query. 
    int success = sqlite3_step(dehydrate_statement); 
    // Reset the query for the next use. 
    sqlite3_reset(dehydrate_statement); 
    // Handle errors. 
    if (success != SQLITE_DONE) { 
     NSAssert1(0, @"Error: failed to dehydrate with message '%s'.", sqlite3_errmsg(database)); 
    } 
    // Update the object state with respect to unwritten changes. 
    dirty = NO; 
} 
// Release member variables to reclaim memory. Set to nil to avoid over-releasing them 
// if dehydrate is called multiple times. 
[movie release]; 
movie = nil; 
[data release]; 
data = nil; 
// Update the object state with respect to hydration. 
hydrated = NO; 
} 
@end 

Answer 1

これはあなたの質問に直接答えませんが、私は3.0 SDKに追加された新しいCoreData APIを調べることをお勧めします。リレーショナル・データをモデリングし、手動でSQLを処理することができます。これにより、コードが少なくて済み、正しく実行されればパフォーマンスが向上します。