memory

DBMS/DBMS/fileManage.cpp

@@ -1,10 +1,10 @@
 #include "fileManage.h"
 #include "data_utility.h"
 
-void FileManage::writePageToFile(int pageid, dbPage pagedata, char* filename){
+void FileManage::writePageToFile(int pageid, dbPage* pagedata, char* filename){
 	FILE* originfilestream;
 	FILE* updatefilestream;
-	char* writedata = dataUtility::data_to_char<dbPage>(pagedata);
+	char* writedata = dataUtility::data_to_char<dbPage>(*pagedata);
 	const char* updatefilename = "newfile.txt";
 	originfilestream = fopen(filename,"r");
 	updatefilestream = fopen(updatefilename, "w+");

DBMS/DBMS/fileManage.h

@@ -4,7 +4,7 @@
 
 class FileManage {
 public:
-	static void writePageToFile(int pageid, dbPage pageinfo, char* filename);
+	static void writePageToFile(int pageid, dbPage* pageinfo, char* filename);
 	static void readPageFromFile(int pageid, dbPage* pageinfo, char* filename);
 	static int createFileFolder(char* filefoldername);
 	static int deleteFileFolder(char* filefoldername);

DBMS/DBMS/globalVariable.h

@@ -5,7 +5,14 @@ typedef unsigned int UINT;
 typedef unsigned short USRT;
 typedef unsigned char BYTE;
 
-#define PAGE_SIZE 8192-sizeof(pageHeader)
+#define DB_PGSIZE			8192 // size of page
+#define DB_PGSIZE_USRT		DB_PGSIZE/(sizeof (USRT)) // count in short
+#define DB_MAX_BUFFER_SIZE	1000 // the size of maximum buffer page
+#define DB_MAX_FILE_NUM		((1<<8*(sizeof (USRT)))-1)
+#define DB_DEFAULT_FILE_SIZE	1048576 //(1024*1024)
+#define DB_MAX_TABLE_NUM	1024
+
+#define PAGE_SIZE DB_PGSIZE-sizeof(pageHeader)
 #define INT_TYPE 0
 #define DOUBLE_TYPE 1
 #define FLOAT_TYPE 2

DBMS/DBMS/main.cpp

@@ -5,16 +5,27 @@
 
 int main()
 {
-	// test buffer jjjjj
-	FileBuffer* fb = new FileBuffer(12);
-	Node *p1 = new Node("aaa", 1), *p2 = new Node("bbb", 2);
-	fb -> insert(p1);
-	fb -> insert(p2);
-	Node *p3 = fb -> find(1);
-	if (p3) cout << p3 -> data << endl;
+	// test buffer
+	FileBuffer* fb = new FileBuffer();
+	Node *p1 = new Node(new dbPage("Jason"))
+		, *p2 = new Node(new dbPage("Alexia"));
+	fb -> insert(rowID(0,1), p1);
+	fb -> insert(rowID(0,2), p2);
+	Node *p3 = fb -> find(rowID(0,1));
+	if (p3) cout << p3 -> page -> data << endl;
+	p3 = fb->find(rowID(0,2));
+	if (p3) cout << p3 -> page -> data;
 	fb -> remove();
-	p3 = fb -> find(1);
-	if (!p3) cout << "null" << endl;
+	if(p3 = fb->find(rowID(0,2)))
+		cout << p3->page->data << " still here" << endl;
+	else
+		cout << " is gone" << endl;
+	p3 = fb -> find(rowID(0,1));
+	if (p3) 
+		cout << p3->page->data << " still here" << endl;
+	else
+		cout << "Jason is gone" << endl;
+
 
 	// test file read or write by page
 	DBStorage testdb("studentManage", 0, 1);

DBMS/DBMS/node.cpp

@@ -1,51 +1,39 @@
 #include "node.h"
 
-FileBuffer::FileBuffer(int max){
-	head = new Node();
-	pointer = new Node();
-	head -> next = pointer;
-	pointer -> pre = head;
-
-	maxPage = max;
-	usedPage = 0;
+FileBuffer::FileBuffer(){
+	numPage = 0;
 }
 
 Node* FileBuffer::remove(){
-	if (!usedPage) return NULL;
-
-	Node* cur = pointer -> pre;
-	(cur -> pre) -> next = pointer;
-	pointer -> pre = cur -> pre;
-
-	if (cur -> dirty) {
-		//FileManage::writePageToFile(cur -> pageid, cur -> data, filename);
+	if (!numPage) return NULL;
+
+	map<rowID, Node*>::iterator it = bufmap.end();
+	Node* bufPage = (--it)->second;
+
+	if ( bufPage->dirty ) {
+		//FileManage::writePageToFile(it->first.first, bufPage -> page
+		//	, bufPage->page->header.fileId );
 	}
-	bufmap.erase(cur -> pageid);
-	usedPage--;
-	return cur;
+
+	bufmap.erase(it);
+	numPage--;
+	return bufPage;
 }
 
-void FileBuffer::insert(Node* cur){
-	if ( usedPage == maxPage ) {
+void FileBuffer::insert(rowID id, Node* buffer){
+	if ( numPage == DB_MAX_BUFFER_SIZE ) {
 		cout << "buffer is full" << endl;
 		remove();
-		insert(cur);
-		return;
 	}
+	bufmap[id] = buffer;
+	numPage++;
+}
 
-	cur -> next = head -> next;
-	cur -> pre = head;
-	head -> next = cur;
-	(cur -> next) -> pre = cur;
-
-	bufmap.insert(map<int, Node*>::value_type(cur -> pageid, cur));
-	usedPage++;
+Node* FileBuffer::find(rowID id){
+	map<rowID, Node*>::iterator it = bufmap.find(id);
+	return (it==bufmap.end())?NULL:it->second;
 }
 
-Node* FileBuffer::find(int pageid){
-	Node* cur = NULL;
-	map<int, Node*>::iterator it = bufmap.find(pageid);
-	if(it != bufmap.end())
-		cur = it ->second;
-	return cur;
+Node* FileBuffer::find(UINT FileID, UINT PageID){
+	return find(pair<UINT,UINT>(FileID,PageID));
 }

DBMS/DBMS/node.h

@@ -9,40 +9,33 @@
 
 using namespace std;
 
+typedef pair<UINT,UINT> rowID;
+
 class FileBuffer;
 struct Node{
-	char* data;
-	int pageid;
 	bool dirty;
-	Node* next;
-	Node* pre;
+	dbPage* page;
 	Node(){
-		data = NULL;
-		pageid = 0;
 		dirty = false;
-		next = NULL;
-		pre = NULL;
+		page = NULL;
 	}
-	Node(char* _data, int _pageid) : data(_data), pageid(_pageid){
+	Node(dbPage* _page) : page(_page){
 		dirty = false;
-		next = NULL;
-		pre = NULL;
 	}
 };
 
 
 //���ÿ���ļ�һ������
 class FileBuffer{
-	Node *head, *pointer;
-	char* filename;
-	int maxPage;
-	int usedPage;
-	map<int, Node*> bufmap;		//�ܹ�����pageid�����ҵ�Node
 public:
-	FileBuffer(int max);
+	FileBuffer();
 	Node* remove();				//�Ӷ��е�β��ɾ��������map��ɾ����usepagenum --
-	void insert(Node* cur);		//������ף�����map��usepagenum ++
-	Node* find(int pageid);		//���ڣ����ؽڵ㣻���򣬷���NULL
+	void insert(rowID id, Node* buffer);		//������ף�����map��usepagenum ++
+	Node* find(rowID id);		//���ڣ����ؽڵ㣻���򣬷���NULL
+	Node* find(UINT FileID, UINT PageID);
+private:
+	int numPage;
+	map<rowID, Node*> bufmap;		//�ܹ�����rowid�����ҵ�Node
 };
 
 

DBMS/DBMS/pageManage.h

@@ -21,7 +21,11 @@ class dbPage {
 	pageHeader header;
 	char data[PAGE_SIZE];
 	dbPage() {
-		memset(data, 0, PAGE_SIZE);
+		memset(data, '/0', PAGE_SIZE);
+	}
+	dbPage(char* src){
+		memset(data, '/0', PAGE_SIZE);
+		strcpy(data,src);
 	}
 };
 

DBMS/DBMS/recordManage.cpp

@@ -52,7 +52,7 @@ void DBStorage::createTable(char* filename, char* databasename, attr tableinfo)
 
 	memcpy(test.data, attrdata, sizeof(tableinfo));
 
-	FileManage::writePageToFile(test.header.pageId, test, path);
+	FileManage::writePageToFile(test.header.pageId, &test, path);
 	this->filenum++;
 
 	dbPage* result = new dbPage();