iOS对FMDB进行封装实现数据持久化资源-CSDN文库

共35个文件

svn-base：20个

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m：6个

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在iOS开发中，数据持久化是一项重要的任务，它允许应用程序在用户关闭或设备重启后仍然保存数据。FMDB是一个流行的选择，它是SQLite数据库的一个Objective-C封装库，提供了简单易用的接口来执行SQL语句。本篇文章将深入探讨如何通过二次封装FMDB实现iOS中的数据持久化，并参考文件`ReadMeForLHMFMDBManager`提供的详细用法。我们需要了解数据持久化的基础概念。数据持久化是指将程序运行过程中的数据保存到非易失性存储（如硬盘）中，以便在后续的程序运行中能够恢复这些数据。在iOS中，常见的数据持久化方法包括文件系统、NSUserDefaults、CoreData以及SQLite等。FMDB是基于SQLite，它是一个轻量级的关系型数据库，适合处理大量结构化数据。接下来，我们来看看如何使用FMDB进行数据持久化。FMDB的核心类有`FMDatabase`、`FMResultSet`和`FMDatabaseQueue`。`FMDatabase`用于打开和管理数据库连接，执行SQL语句；`FMResultSet`是查询结果的迭代器；`FMDatabaseQueue`则提供了线程安全的数据库操作。二次封装FMDB通常是为了简化API，使其更符合iOS开发的习惯，以及提供更强大的功能。例如，可以创建一个名为`LHMFMDBManager`的类，包含以下功能： 1. 数据库初始化：在`LHMFMDBManager`中初始化数据库连接，设置数据库路径，并创建必要的表结构。 ```objc + (instancetype)sharedInstance { static LHMFMDBManager *manager; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ manager = [[self alloc] init]; [manager setupDatabase]; }); return manager; } - (void)setupDatabase { // 设置数据库路径 NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; path = [path stringByAppendingPathComponent:@"MyDatabase.sqlite"]; // 打开数据库 self.db = [FMDatabase databaseWithPath:path]; if (![self.db open]) { NSLog(@"Failed to open database"); } // 创建表 [self.db executeUpdate:@"CREATE TABLE IF NOT EXISTS MyTable (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER)"]; } ``` 2. 数据插入：封装一个方法，接受模型对象并将其转换为SQL语句进行插入。 ```objc - (BOOL)insertObject:(NSObject *)object { if (![object conformsToProtocol:@protocol(LHMFMBManagedObject)]) { NSLog(@"对象不遵循LHMFMBManagedObject协议"); return NO; } NSString *sql = [object createInsertSQL]; return [self.db executeUpdate:sql]; } ``` 3. 数据查询：封装查询方法，返回`FMResultSet`，并提供便利的方法获取查询结果。 ```objc - (FMResultSet *)executeQuery:(NSString *)sql { return [self.db executeQuery:sql]; } - (NSArray *)queryObjectsWithSQL:(NSString *)sql { NSMutableArray *results = [NSMutableArray array]; FMResultSet *rs = [self executeQuery:sql]; while ([rs next]) { NSObject *object = [rs resultDictionary]; [results addObject:object]; } [rs close]; return results; } ``` 4. 更新与删除：同样提供更新和删除数据的方法，根据SQL语句进行操作。 5. 错误处理：封装错误处理机制，方便在出错时捕获并打印错误信息。通过以上封装，我们可以更方便地在项目中使用FMDB，无需关心数据库连接的创建、关闭以及SQL语句的执行细节。只需调用`LHMFMDBManager`的相关方法，即可完成数据的增删改查，大大提高了开发效率。总结来说，对FMDB进行封装，主要目的是简化操作，提高代码可读性和复用性。在`ReadMeForLHMFMDBManager`文档中，应详细介绍了如何使用这个封装后的类进行数据持久化操作，包括实例化、数据操作以及异常处理等步骤。通过学习和使用这样的封装，开发者可以更专注于业务逻辑，而不用过多关注底层数据库操作。

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WSFMDBManger.zip （35个子文件）

WSFMDBManger

FMDB

FMDatabase.h 4KB

FMResultSet.h 3KB

FMDatabaseAdditions.h 1KB

FMResultSet.m 12KB

FMDatabasePool.m 6KB

FMDatabasePool.h 2KB

.svn

all-wcprops 2KB

prop-base

FMDatabaseAdditions.h.svn-base 29B

FMDatabasePool.m.svn-base 29B

FMDatabaseQueue.h.svn-base 29B

FMDatabasePool.h.svn-base 29B

FMResultSet.m.svn-base 29B

FMDatabase.m.svn-base 29B

FMResultSet.h.svn-base 29B

FMDatabaseAdditions.m.svn-base 29B

FMDatabase.h.svn-base 29B

FMDatabaseQueue.m.svn-base 29B

props

tmp

prop-base

props

text-base

FMDatabaseAdditions.h.svn-base 1KB

FMDatabasePool.m.svn-base 6KB

FMDatabaseQueue.h.svn-base 1022B

FMDatabasePool.h.svn-base 2KB

FMResultSet.m.svn-base 12KB

FMDatabase.m.svn-base 33KB

FMResultSet.h.svn-base 3KB

FMDatabaseAdditions.m.svn-base 5KB

FMDatabase.h.svn-base 4KB

FMDatabaseQueue.m.svn-base 4KB

entries 2KB

FMDatabaseAdditions.m 5KB

FMDatabaseQueue.h 1022B

FMDatabaseQueue.m 4KB

FMDatabase.m 33KB

WSDBManager.h 1KB

ReadMeForLHMFMDBManager.strings 1KB

WSDBManager.m 5KB

#import <Foundation/Foundation.h> #import "sqlite3.h" #import "FMResultSet.h" #import "FMDatabasePool.h" #if ! __has_feature(objc_arc) #define FMDBAutorelease(__v) ([__v autorelease]); #define FMDBReturnAutoreleased FMDBAutorelease #define FMDBRetain(__v) ([__v retain]); #define FMDBReturnRetained FMDBRetain #define FMDBRelease(__v) ([__v release]); #define FMDBDispatchQueueRelease(__v) (dispatch_release(__v)); #else // -fobjc-arc #define FMDBAutorelease(__v) #define FMDBReturnAutoreleased(__v) (__v) #define FMDBRetain(__v) #define FMDBReturnRetained(__v) (__v) #define FMDBRelease(__v) #if TARGET_OS_IPHONE // Compiling for iOS #if __IPHONE_OS_VERSION_MIN_REQUIRED >= 60000 // iOS 6.0 or later #define FMDBDispatchQueueRelease(__v) #else // iOS 5.X or earlier #define FMDBDispatchQueueRelease(__v) (dispatch_release(__v)); #endif #else // Compiling for Mac OS X #if MAC_OS_X_VERSION_MIN_REQUIRED >= 1080 // Mac OS X 10.8 or later #define FMDBDispatchQueueRelease(__v) #else // Mac OS X 10.7 or earlier #define FMDBDispatchQueueRelease(__v) (dispatch_release(__v)); #endif #endif #endif @interface FMDatabase : NSObject { sqlite3* _db; NSString* _databasePath; BOOL _logsErrors; BOOL _crashOnErrors; BOOL _traceExecution; BOOL _checkedOut; BOOL _shouldCacheStatements; BOOL _isExecutingStatement; BOOL _inTransaction; int _busyRetryTimeout; NSMutableDictionary *_cachedStatements; NSMutableSet *_openResultSets; NSMutableSet *_openFunctions; } @property (atomic, assign) BOOL traceExecution; @property (atomic, assign) BOOL checkedOut; @property (atomic, assign) int busyRetryTimeout; @property (atomic, assign) BOOL crashOnErrors; @property (atomic, assign) BOOL logsErrors; @property (atomic, retain) NSMutableDictionary *cachedStatements; + (id)databaseWithPath:(NSString*)inPath; - (id)initWithPath:(NSString*)inPath; - (BOOL)open; #if SQLITE_VERSION_NUMBER >= 3005000 - (BOOL)openWithFlags:(int)flags; #endif - (BOOL)close; - (BOOL)goodConnection; - (void)clearCachedStatements; - (void)closeOpenResultSets; - (BOOL)hasOpenResultSets; // encryption methods. You need to have purchased the sqlite encryption extensions for these to work. - (BOOL)setKey:(NSString*)key; - (BOOL)rekey:(NSString*)key; - (NSString *)databasePath; - (NSString*)lastErrorMessage; - (int)lastErrorCode; - (BOOL)hadError; - (NSError*)lastError; - (sqlite_int64)lastInsertRowId; - (sqlite3*)sqliteHandle; - (BOOL)update:(NSString*)sql withErrorAndBindings:(NSError**)outErr, ...; - (BOOL)executeUpdate:(NSString*)sql, ...; - (BOOL)executeUpdateWithFormat:(NSString *)format, ...; - (BOOL)executeUpdate:(NSString*)sql withArgumentsInArray:(NSArray *)arguments; - (BOOL)executeUpdate:(NSString*)sql withParameterDictionary:(NSDictionary *)arguments; - (FMResultSet *)executeQuery:(NSString*)sql, ...; - (FMResultSet *)executeQueryWithFormat:(NSString*)format, ...; - (FMResultSet *)executeQuery:(NSString *)sql withArgumentsInArray:(NSArray *)arguments; - (FMResultSet *)executeQuery:(NSString *)sql withParameterDictionary:(NSDictionary *)arguments; - (BOOL)rollback; - (BOOL)commit; - (BOOL)beginTransaction; - (BOOL)beginDeferredTransaction; - (BOOL)inTransaction; - (BOOL)shouldCacheStatements; - (void)setShouldCacheStatements:(BOOL)value; #if SQLITE_VERSION_NUMBER >= 3007000 - (BOOL)startSavePointWithName:(NSString*)name error:(NSError**)outErr; - (BOOL)releaseSavePointWithName:(NSString*)name error:(NSError**)outErr; - (BOOL)rollbackToSavePointWithName:(NSString*)name error:(NSError**)outErr; - (NSError*)inSavePoint:(void (^)(BOOL *rollback))block; #endif + (BOOL)isSQLiteThreadSafe; + (NSString*)sqliteLibVersion; - (int)changes; - (void)makeFunctionNamed:(NSString*)name maximumArguments:(int)count withBlock:(void (^)(sqlite3_context *context, int argc, sqlite3_value **argv))block; @end @interface FMStatement : NSObject { sqlite3_stmt *_statement; NSString *_query; long _useCount; } @property (atomic, assign) long useCount; @property (atomic, retain) NSString *query; @property (atomic, assign) sqlite3_stmt *statement; - (void)close; - (void)reset; @end

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