iOS中FMDB的增、删、改、查

FMDB 是对SQlite的封装，面向对象
FMDatabase： 用来执行(增、删、改、查)的SQL语句
FMResultSet：表示在' '上执行查询的结果

使用步骤分为：创建数据库——创建表——插入数据——修改数据——查询数据——删除
1、创建并打开数据库

- (void)openSqlite {
    NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *path = [docPath stringByAppendingPathComponent:@"Person.fmdb"];
    self.db = [FMDatabase databaseWithPath:path];
    [self.db open];
}

2、创建表：使用runtime获取自定义类对象的所有成员变量，依次赋值，由于调用了C语言的API，需要手动释放free()

-(void)createTableWithClass:(Class)clazz
{
    [self openSqlite];
    NSString *sql = @"CREATE TABLE IF NOT EXISTS ";
    const char *tableName = class_getName(clazz);
    sql = [sql stringByAppendingString:[[NSString alloc] initWithUTF8String:tableName]];
//    sql = [sql stringByAppendingString:@"(ID INTEGER PRIMARY KEY AUTOINCREMENT,"];
    sql = [sql stringByAppendingString:@" ("];
    unsigned int count = 0;
    objc_property_t *propertys = class_copyPropertyList(clazz, &count);
    for (int i=0; i

3、插入一个自定义对象
obj为自定义的模型对象

-(void)insertWithObj:(id)obj
{
    if (![self.db open]) {
        return;
    }
    const char *tableName = class_getName([obj class]);
    NSString *tableNameStr =[[NSString alloc] initWithUTF8String:tableName];
    
    NSString *sql = [NSString stringWithFormat:@"insert into %@ (",tableNameStr];
    NSString *sqlValues =@"(";
    unsigned int count = 0;
    objc_property_t *propertys = class_copyPropertyList([obj class], &count);
    
    for (int i=0; i

4、更新一条数据：
obj为表中存储的模型对象
keyName为模型对象的属性
value为模型对象中属性对应的值

-(void)updateWithObj:(id)obj andKey:(NSString*)keyName isEqualValue:(NSString*)value
{
    if (![self.db open]) {
        return;
    }
    const char *tableName = class_getName([obj class]);
    NSString *tableNameStr =[[NSString alloc] initWithUTF8String:tableName];
    NSString *sql = [NSString stringWithFormat:@"UPDATE %@ SET ",tableNameStr];
    unsigned int count = 0;
    objc_property_t *propertys = class_copyPropertyList([obj class], &count);
    for (int i=0; i

5、根据条件删除记录:
params示例：@"ID = 1"

-(void)deleteOneRecordWithClass:(Class)clazz params:(NSString*)params
{
    if (params==nil)
    {
        params = @" 1=1";
    }
    const char *tableName = class_getName(clazz);
    NSString *tableNameStr =[[NSString alloc] initWithUTF8String:tableName];
    NSString *sql = [NSString stringWithFormat:@"DELETE FROM %@ WHERE %@",tableNameStr,params];
    BOOL res = [self.db executeUpdate:sql];
    if (res) {
        NSLog(@"删除成功");
    }else {
        NSLog(@"删除失败");
    }
}

6、查询当前表中所有数据

-(NSMutableArray *)selectAllWithClass:(Class)clazz
{
    if (![self.db open]) {
        return [NSMutableArray array];
    }
    NSMutableArray *data = [NSMutableArray array];
    const char *tableName = class_getName(clazz);
    NSString *tableNameStr =[[NSString alloc] initWithUTF8String:tableName];
    NSString *sql = [NSString stringWithFormat:@"SELECT * FROM %@ WHERE  1=1",tableNameStr];
    FMResultSet *rs = [self.db executeQuery:sql];
    unsigned int count = 0;
    objc_property_t *propertys = class_copyPropertyList(clazz, &count);
    while ([rs next]) {
        id obj = [[clazz alloc] init];
        for (int i=0; i

使用示例：
1、新建FmdbTool单例类包含以上方法，管理数据
2、自定义模型PersonVO
代码：

//创建数据库和表
    [[FmdbTool shareManager] createTableWithClass:[PersonVO class]];
    NSMutableArray *temArr = [NSMutableArray array];
    for (int i=0; i<5; i++) {
        PersonVO *p = [PersonVO new];
        p.goodsName = @"魏无羡";
        p.shopNo = @"123";
        p.ID = [NSString stringWithFormat:@"%d",i];
        //插入数据
        [[FmdbTool shareManager] insertWithObj:p];
        [temArr addObject:p];
    }
    PersonVO *p1 = temArr[1];
    p1.goodsName = @"你好";
    p1.shopNo = @"111";
    //更新temArr中的第2条数据
    [[FmdbTool shareManager] updateWithObj:p1 andKey:@"ID" isEqualValue:p1.ID];
    //删除ID==4的数据
    [[FmdbTool shareManager] deleteOneRecordWithClass:[PersonVO class] params:@"ID = 4"];
    NSMutableArray *arr = [[FmdbTool shareManager] selectAllWithClass:[PersonVO class]];
    for (PersonVO *p in arr) {
        NSLog(@"获取ID--%@,shopNo--%@,goodsName--%@",p.ID,p.shopNo,p.goodsName);
    }

打印：

2022-03-03 09:27:04.139699+0800 OCTest[2163:36965] 建表成功
2022-03-03 09:27:04.141687+0800 OCTest[2163:36965] 插入数据成功
2022-03-03 09:27:04.143948+0800 OCTest[2163:36965] 插入数据成功
2022-03-03 09:27:04.146022+0800 OCTest[2163:36965] 插入数据成功
2022-03-03 09:27:04.148426+0800 OCTest[2163:36965] 插入数据成功
2022-03-03 09:27:04.150843+0800 OCTest[2163:36965] 插入数据成功
2022-03-03 09:27:04.152985+0800 OCTest[2163:36965] 更新数据成功
2022-03-03 09:27:04.154903+0800 OCTest[2163:36965] 删除成功
2022-03-03 09:27:04.155475+0800 OCTest[2163:36965] 获取ID--0,shopNo--123,goodsName--魏无羡
2022-03-03 09:27:04.155674+0800 OCTest[2163:36965] 获取ID--1,shopNo--111,goodsName--你好
2022-03-03 09:27:04.155839+0800 OCTest[2163:36965] 获取ID--2,shopNo--123,goodsName--魏无羡
2022-03-03 09:27:04.155984+0800 OCTest[2163:36965] 获取ID--3,shopNo--123,goodsName--魏无羡