github_31804537的博客

2.2. Fields and Tuples Tuples in SimpleDB are quite basic. They consist of a collection of Field objects, one per field in the Tuple. Field is an interface that different data types (e.g., integer,

The catalog (class Catalog in SimpleDB) consists of a list of the tables and schemas of the tables that are currently in the database. You will need to support the ability to add a new table, as well a

现在还在项目一所以多线程加锁等待这一块没写，一开始没看到写了锁写了很麻烦，才发现不用写，也没测试，所以就没写，等以后做到再加上去。 写BufferPool是用map来缓存数据，但不知道TransactionId在这个函数有什么用，。没用到这个参数，代码如下，其实就两个函数public class BufferPool { /** * Bytes per page, includi

这次感觉比前几次都难，尤其卡在了iterator上，需要反复阅读上面的说明，说明在DbfileIterator上，。详细代码如下HeapFile.java 在文本编译器上删的sout测试语句，可能会带来一些错误，欢迎指正public class HeapFile implements DbFile { /** * Constructs a heap file backed by t

public class SeqScan implements DbIterator { private static final long serialVersionUID = 1L; TransactionId tid; int tableid; String tableAlia; DbFile dbFile; DbFileIterator dbFi

我一般不把他写的todo去掉，万一以后改防止改错了。前两个主要实现filter方法，因为后面要用 先放上Predicate.javapackage simpledb;import java.io.Serializable;/** * Predicate compares tuples to a specified Field value. */public class Predicate