SQLite与FMDB

第三方：FMDateBase ,需导入libsqlite3.tbd
另一个常用数据库：realm

创建表

    NSString *path = @"/Users/apple/Desktop/dataBase.sqlite";
    _dataBase = [FMDatabase databaseWithPath:path];
    //如果要操作dataBase必须先要打开
    if (![_dataBase open]) {
        [_dataBase open];
    }
    //创建表
    [_dataBase executeUpdate:@"create   table if not exists 'Person' (Name text,Age integer)"];
    //用完关闭
    [_dataBase close];

插入数据

1. 完整SQL插入

NSString *insertSQL = @"INSERT INTO Student (name, age,address) VALUES ('张三', 23, '长沙')";
if ([database executeUpdate:insertSQL]) {
         NSLog(@"insert OK");
}
else {
         NSLog(@"Insert Error: %@", database.lastErrorMessage);
}

2. 使用占位符SQL插入

NSString *insertSQL = @"INSERT INTO Student (name, age, address) VALUES (?, ?, ?)";
//后面的参数使用与C语言中类型对应的Objective-C对象
if ([database executeUpdate:insertSQL, @"李四", @19, @"长沙"]) {
    NSLog(@"insert OK");
}
else {
    NSLog(@"Insert Error: %@", database.lastErrorMessage);
}

NSString *insertSQL = @"INSERT INTO Student (name, age, address) VALUES (%@, %@, %@)";
if ([database executeUpdateWithFormat:insertSQL, @"张三", @20, @"长沙"]) {
    %@ NSLog(@"Insert Error: %@", database.lastErrorMessage);
    NSLog(@"insert OK");
}
else { 
    NSLog(@"Insert Error: %@", database.lastErrorMessage);
}

3. 带字典的占位符SQL插入

NSString *insertSQL = @"INSERT INTO Student (name, age, address) VALUES (:name, :age, :address)";
NSDictionary *dict = @{@"name":@"张三", @"age":@18, @"address":@"长沙"};
if ([database executeUpdate:insertSQL withParameterDictionary:dict]) {
    NSLog(@"insert OK");
} else {
    NSLog(@"Insert Error: %@", database.lastErrorMessage);
}

FMDB查询数据

NSString *querySQL = @"SELECT * FROM Student";
//1.  执行查询操作
FMResultSet *rs = [database executeQuery:querySQL];
//2.  获取一条记录, 成功还回YES
while ([rs next]) {
        //3.  通过字段名获取数据
        NSInteger stuId = [rs longForColumn:@"stuId"];
        //4.  通过字段位置获取数据
        NSString *name = [rs stringForColumnIndex:1];
        int age = [rs intForColumnIndex:2];
        NSString *address = [rs stringForColumn:@"address"];
        NSLog(@"%ld:%@:%d:%@", stuId, name, age, address);
}

NSString *querySQL = @"SELECT * FROM Student";
[database executeStatements:querySQLwithResultBlock:^int(NSDictionary *resultsDictionary) {
        //多次调用, 每次用字典返回一条记录 
        NSLog(@"%@", resultsDictionary);
        return 0;
}];

FMDB多线程

1. 多线程队列

databaseQueueWithPath:path];[queue inDatabase:^(FMDatabase *db) {
        [db executeUpdate:@"INSERT INTO Student (name, age,address) VALUES ('张三', 29, '长沙')"];
        [db executeUpdate:@"INSERT INTO Student (name, age,address) VALUES ('李四', 27, '娄底')"];
        [db executeUpdate:@"INSERT INTO Student (name, age,address) VALUES ('王五', 24, '常德')"];}];

2. 支持事务操作

[queue inTransaction:^(FMDatabase *db, BOOL *rollback) {
        [db executeUpdate:@"INSERT INTO Student (name, age, address)VALUES (' ', 29, ' ')"];
        [db executeUpdate:@"INSERT INTO Student (name, age, address)VALUES (' ', 27, ' ')"];
        // 回滚
        //        if (某种条件) {
        //                  *rollback = YES;
        //                  return;
        //        }
        [db executeUpdate:@"INSERT INTO Student (name, age, address)VALUES (' ', 24, ' ')"];
}];