let imageView = UIImageView(frame: CGRect(x:10, y:100, width:300, height:66))
let image = UIImage(named: "bg")?
    .resizableImage(withCapInsets: UIEdgeInsets(top: 0, left: 15, bottom: 0, right: 15),
                    resizingMode: .stretch) //左右15像素的部分不变，中间部分来拉伸
imageView.image = image
view.addSubview(imageView)

ColumnConstraintBinding(
    isPrimary: Bool = false, // 该字段是否为主键。字段约束中只能同时存在一个主键
    orderBy term: OrderTerm? = nil, // 当该字段是主键时，存储顺序是升序还是降序
    isAutoIncrement: Bool = false, // 当该字段是主键时，其是否支持自增。只有整型数据可以定义为自增。
    onConflict conflict: Conflict? = nil, // 当该字段是主键时，若产生冲突，应如何处理
    isNotNull: Bool = false, // 该字段是否可以为空
    isUnique: Bool = false, // 该字段是否可以具有唯一性
    defaultTo defaultValue: ColumnDef.DefaultType? = nil // 该字段在数据库内使用什么默认值
)

let autoIncrementObject = Sample()
autoIncrementObject.isAutoIncrement = true

// 插入自增数据
try database.insert(objects: autoIncrementObject, intoTable: "sampleTable")
print(autoIncrementObject.lastInsertedRowID) // 输出 1

// 再次插入自增数据
try database.insert(objects: autoIncrementObject, intoTable: "sampleTable")
print(autoIncrementObject.lastInsertedRowID) // 输出 2

// 插入非自增的指定数据
let specificObject = Sample()
specificObject.identifier = 10
try database.insert(objects: specificObject, intoTable: "sampleTable")

class Sample: TableCodable {
    var identifier: Int? = nil
    var description: String? = nil
    var multiIndexPart1: Int = 0
    var multiIndexPart2: Int = 0
        
    enum CodingKeys: String, CodingTableKey {
        typealias Root = Sample
        static let objectRelationalMapping = TableBinding(CodingKeys.self)
        case identifier
        case description
        case multiIndexPart1
        case multiIndexPart2

        static var indexBindings: [IndexBinding.Subfix: IndexBinding]? {
            return [
                "_uniqueIndex": IndexBinding(isUnique: true, indexesBy: identifier),
                "_descendingIndex": IndexBinding(indexesBy: description.asIndex(orderBy: .descending)),
                "_multiIndex": IndexBinding(indexesBy: multiIndexPart1, multiIndexPart2.asIndex(orderBy: .ascending))
            ]
        }
    }
}

class Sample: TableCodable {
    var identifier: Int? = nil
    var multiPrimaryKeyPart1: Int = 0
    var multiPrimaryKeyPart2: Int = 0
    var multiUniquePart1: Int = 0
    var multiUniquePart2: Int = 0
        
    enum CodingKeys: String, CodingTableKey {
        typealias Root = Sample
        static let objectRelationalMapping = TableBinding(CodingKeys.self)
        case identifier
        case multiPrimaryKeyPart1
        case multiPrimaryKeyPart2
        case multiUniquePart1
        case multiUniquePart2

        static var tableConstraintBindings: [TableConstraintBinding.Name: TableConstraintBinding]? {
            let multiPrimaryBinding =
                MultiPrimaryBinding(indexesBy: multiPrimaryKeyPart1.asIndex(orderBy: .descending), multiPrimaryKeyPart2)
            let multiUniqueBinding =
                MultiUniqueBinding(indexesBy: multiUniquePart1, multiUniquePart2.asIndex(orderBy: .ascending))
            return [
                "MultiPrimaryConstraint": multiPrimaryBinding,
                "MultiUniqueConstraint": multiUniqueBinding
            ]
        }
    }
}

func delete(fromTable table: String, // 表名
            where condition: Condition? = nil, // 符合删除的条件
            orderBy orderList: [OrderBy]? = nil, // 排序的方式
            limit: Limit? = nil, // 删除的个数
            offset: Offset? = nil // 从第几个开始删除
) throws

// 删除 sampleTable 中所有 identifier 大于 1 的行的数据
try database.delete(fromTable: "sampleTable", 
                    where: Sample.Properties.identifier > 1)

// 删除 sampleTable 中 identifier 降序排列后的前 2 行数据
try database.delete(fromTable: "sampleTable", 
                    orderBy: Sample.Properties.identifier.asOrder(by: .descending), 
                    limit: 2)

// 删除 sampleTable 中 description 非空的数据，按 identifier 降序排列后的前 3 行的后 2 行数据
try database.delete(fromTable: "sampleTable", 
                    where: Sample.Properties.description.isNotNull(), 
                    orderBy: Sample.Properties.identifier.asOrder(by: .descending), 
                    limit: 2,
                    offset: 3)

// 删除 sampleTable 中的所有数据
try database.delete(fromTable: "sampleTable")

let object = Sample()
object.description = "update"

// 将 sampleTable 中所有 identifier 大于 1 且 description 字段不为空 的行的 description 字段更新为 "update"
try database.update(table: "sampleTable"
                    on: Sample.Properties.description,
                    with: object,
                    where: Sample.Properites.identifier > 1 && Sample.Properties.description.isNotNull())

// 将 sampleTable 中前三行的 description 字段更新为 "update"
try database.update(table: "sampleTable"
                    on: Sample.Properties.description,
                    with: object,
                    limit: 3)

let row: [ColumnCodableBase] = ["update"]

// 将 sampleTable 中所有 identifier 大于 1 且 description 字段不为空 的行的 description 字段更新为 "update"
try database.update(table: "sampleTable"
                    on: Sample.Properties.description,
                    with: row,
                    where: Sample.Properites.identifier > 1 && Sample.Properties.description.isNotNull())

// 将 sampleTable 中前三行的 description 字段更新为 "update"
try database.update(table: "sampleTable"
                    on: Sample.Properties.description,
                    with: row,
                    limit: 3)

// 返回 sampleTable 中的所有数据
let allObjects: [Sample] = try database.getObjects(fromTable: "sampleTable")

// 返回 sampleTable 中 identifier 小于 5 或 大于 10 的行的数据
let objects: [Sample] = try database.getObjects(fromTable: "sampleTable", 
                                                where: Sample.Properties.identifier < 5 || Sample.Properties.identifier > 10)

// 返回 sampleTable 中 identifier 最大的行的数据
let object: Sample? = try database.getObject(fromTable: "sampleTable", 
                                             orderBy: Sample.Properties.identifier.asOrder(by: .descending))

let objects: [Sample] = try database.getObjects(fromTable: "sampleTable", 
                                                on: Sample.Properties.identifier)

// 获取所有内容
let allRows = try database.getRows(fromTable: "sampleTable")
print(allRows[row: 2, column: 0].int32Value) // 输出 3

// 获取第二行
let secondRow = try database.getRow(fromTable: "sampleTable", offset: 1)
print(secondRow[0].int32Value) // 输出 2

// 获取 description 列
let descriptionColumn = try database.getColumn(on: Sample.Properties.description, fromTable: "sampleTable")
print(descriptionColumn) // 输出 "sample1", "sample1", "sample1", "sample2", "sample2" 

// 获取不重复的 description 列的值
let distinctDescriptionColumn = try database.getDistinctColumn(on: Sample.Properties.description, fromTable: "sampleTable")
print(distinctDescriptionColumn) // 输出 "sample1", "sample2"

// 获取第二行 description 列的值
let value = try database.getValue(on: Sample.Properties.description, offset: 1)
print(value.stringValue) // 输出 "sample1"

// 获取 identifier 的最大值
let maxIdentifier = try database.getValue(on: Sample.Properties.identifier.max(), fromTable: "sampleTable")

// 获取不重复的 description 的值
let distinctDescription = try database.getDistinctValue(on: Sample.Properties.description, fromTable: "sampleTable")
print(distinctDescription.stringValue) // 输出 "sample1"

override func viewDidLoad() {
  	super.viewDidLoad()

    DispatchQueue.main.sync {
    	print("deadlock")
    }
}
或者
dispatch_queue_t serialQueue = dispatch_queue_create("test", DISPATCH_QUEUE_SERIAL);

dispatch_async(serialQueue, ^{
       
        dispatch_sync(serialQueue, ^{
            
            NSLog(@"deadlock");
        });
    });

dispatch_queue_t serialQueue = dispatch_queue_create("test", DISPATCH_QUEUE_SERIAL);
    
    NSLog(@"1");
    
    dispatch_async(serialQueue, ^{
        
         NSLog(@"2");
    });
    
    NSLog(@"3");
    
    dispatch_sync(serialQueue, ^{
        
        NSLog(@"4");
    });
    
    NSLog(@"5");

- (id)readDataForKey:(NSString *)key
{
    __block id result;
    
    dispatch_sync(_concurrentQueue, ^{
       
        result = [self valueForKey:key];
    });
    
    return result;
}

- (void)writeData:(id)data forKey:(NSString *)key
{
    dispatch_barrier_async(_concurrentQueue, ^{
       
        [self setValue:data forKey:key];
    });
}

dispatch_queue_t concurrentQueue = dispatch_queue_create("test1", DISPATCH_QUEUE_CONCURRENT);

    dispatch_group_t group = dispatch_group_create();
    
    for (NSInteger i = 0; i < 10; i++) {
        
        dispatch_group_async(group, concurrentQueue, ^{
            
            sleep(1);
            
            NSLog(@"%zd:网络请求",i);
        });
    }
    
    dispatch_group_notify(group, dispatch_get_main_queue(), ^{
        
        NSLog(@"刷新页面");
    });

+ (NSThread *)shareThread {
    
    static NSThread *shareThread = nil;
    
    static dispatch_once_t oncePredicate;
    
    dispatch_once(&oncePredicate, ^{
        
        shareThread = [[NSThread alloc] initWithTarget:self selector:@selector(threadTest2) object:nil];
        
        [shareThread setName:@"threadTest"];
        
        [shareThread start];
    });
    
    return shareThread;
}

+ (void)threadTest
{
    @autoreleasepool {
        
        NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
        
        [runLoop addPort:[NSMachPort port] forMode:NSDefaultRunLoopMode];
        
        [runLoop run];
    }
}

struct __AtAutoreleasePool {
  __AtAutoreleasePool() {atautoreleasepoolobj = objc_autoreleasePoolPush();}
  ~__AtAutoreleasePool() {objc_autoreleasePoolPop(atautoreleasepoolobj);}
  void * atautoreleasepoolobj;
};

class AutoreleasePoolPage {
    magic_t const magic;
    id *next;
    pthread_t const thread;
    AutoreleasePoolPage * const parent;
    AutoreleasePoolPage *child;
    uint32_t const depth;
    uint32_t hiwat;
};