在iOS上使用和访问现有的SQLite数据库

使用SQLite可以使SQLite数据库交互变得简单而干净

FBDB framework

参考值得阅读：

FMDB框架文档

带情节提要的示例项目

最初设定

将

SQLite DB

1. 首先下载FMDB框架
2. 现在提取框架，从

   src/fmdb

   文件夹（而不是

   src/sample

   或

   src/extra

   文件夹）中复制所有文件。
3. 单击您的项目在Xpre的左列。
4. 单击中间列中的主要目标。
5. 点击“构建阶段”标签。
6. 展开“将二进制文件与库链接”旁边的箭头。
7. 点击“ +”按钮。
8. 搜索libsqlite3.0.dylib并双击它。

将您的文件复制

existing database

app'sdocument

didFinishLaunchingWithOptions:

在您的AppDelegate中添加以下代码。

AppDelegate.m

#import "AppDelegate.h"@implementation AppDelegate// Application Start- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    // Function called to create a copy of the database if needed.    [self createCopyOfDatabaseIfNeeded];    return YES;}#pragma mark - Defined Functions// Function to Create a writable copy of the bundled default database in the application documents directory.- (void)createCopyOfDatabaseIfNeeded {    // First, test for existence.    BOOL success;    NSFileManager *fileManager = [NSFileManager defaultManager];    NSError *error;    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSdocumentDirectory, NSUserDomainMask, YES);    // Database filename can have extension db/sqlite.    NSString *documentsDirectory = [paths objectAtIndex:0];    NSString *appDBPath = [documentsDirectory stringByAppendingPathComponent:@"database-name.sqlite"];    success = [fileManager fileExistsAtPath:appDBPath];    if (success) {        return;    }    // The writable database does not exist, so copy the default to the appropriate location.    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"database-name.sqlite"];    success = [fileManager copyItemAtPath:defaultDBPath toPath:appDBPath error:&error];    NSAssert(success, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);}

YourViewController.m

选择查询

#import "FMDatabase.h"- (void)getAllData {    // Getting the database path.    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSdocumentDirectory, NSUserDomainMask, YES);    NSString *docsPath = [paths objectAtIndex:0];    NSString *dbPath = [docsPath stringByAppendingPathComponent:@"database-name.sqlite"];    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];    [database open];    NSString *sqlSelectQuery = @"SELECT * FROM tablename";    // Query result     FMResultSet *resultsWithNameLocation = [database executeQuery:sqlSelectQuery];    while([resultsWithNameLocation next]) {        NSString *strID = [NSString stringWithFormat:@"%d",[resultsWithNameLocation intForColumn:@"ID"]];        NSString *strName = [NSString stringWithFormat:@"%@",[resultsWithNameLocation stringForColumn:@"Name"]];        NSString *strLoc = [NSString stringWithFormat:@"%@",[resultsWithNameLocation stringForColumn:@"Location"]];        // loading your data into the array, dictionaries.        NSLog(@"ID = %d, Name = %@, Location = %@",strID, strName, strLoc);    }    [database close];   }

插入查询

#import "FMDatabase.h"- (void)insertData {    // Getting the database path.    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSdocumentDirectory, NSUserDomainMask, YES);    NSString *docsPath = [paths objectAtIndex:0];    NSString *dbPath = [docsPath stringByAppendingPathComponent:@"database-name.sqlite"];    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];    [database open];        NSString *insertQuery = [NSString stringWithFormat:@"INSERT INTO user VALUES ('%@', %d)", @"Jobin Kurian", 25];    [database executeUpdate:insertQuery];       [database close];}

更新查询

- (void)updateDate {    // Getting the database path.    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSdocumentDirectory, NSUserDomainMask, YES);    NSString *docsPath = [paths objectAtIndex:0];    NSString *dbPath = [docsPath stringByAppendingPathComponent:@"fmdb-sample.sqlite"];    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];    [database open];        NSString *insertQuery = [NSString stringWithFormat:@"UPDATE users SET age = '%@' WHERe username = '%@'", @"23", @"colin" ];    [database executeUpdate:insertQuery];    [database close];}

删除查询

#import "FMDatabase.h"- (void)deleteData {    // Getting the database path.    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSdocumentDirectory, NSUserDomainMask, YES);    NSString *docsPath = [paths objectAtIndex:0];    NSString *dbPath = [docsPath stringByAppendingPathComponent:@"database-name.sqlite"];    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];    [database open];    NSString *deleteQuery = @"DELETE FROM user WHERe age = 25";    [database executeUpdate:deleteQuery];       [database close];}

附加功能

获取行数

确保包括

FMDatabaseAdditions.h

intForQuery:

#import "FMDatabase.h"#import "FMDatabaseAdditions.h"- (void)gettingRowCount {    // Getting the database path.    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSdocumentDirectory, NSUserDomainMask, YES);    NSString *docsPath = [paths objectAtIndex:0];    NSString *dbPath = [docsPath stringByAppendingPathComponent:@"database-name.sqlite"];    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];    [database open];    NSUInteger count = [database intForQuery:@"SELECT COUNT(field_name) FROM table_name"];    [database close];}