book.h

This is an example application that shows how to use a SQLlite DB to display information on an iPhon

/*
    File: Book.h
Abstract: 
The Book class manages the in-memory representation of information about a single book.  

 Version: 1.9

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*/

#import <Foundation/Foundation.h>
#import <sqlite3.h>

@interface Book : NSObject {
    // Opaque reference to the underlying database.
    sqlite3 *database;
    // Primary key in the database.
    NSInteger primaryKey;
    // Attributes.
    NSString *title;
    NSDate *copyright;
    NSString *author;
    // 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) NSDate *copyright;
@property (copy, nonatomic) NSString *author;

// 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;

@end