README.md

MiniSQL_IndexManager

IndexManager is one of 6 modules of MiniSQL, project of database design course. You can compile and debug IndexManager without other modules just use make command in your shell.
The structure of the program is listed below:

API

IndexManager class provides 4 interfaces for other modules

class IndexManager {
private:
    /* some code here */
public:
    IndexManager();
    int search_one(const std::string& database, const std::string& table_name, struct index_info& inform);
    void search_many(const std::string& database, const std::string& table_name, int type, struct index_info& inform, std::vector<int>& container);
    void insert_one(const std::string& database, const std::string& table_name, struct index_info& inform);
    void delete_one(const std::string& database, const std::string& table_name, struct index_info& inform);
};

Node definition

Use a 4K block as a B+ tree node. The first byte is used to identify whether it is leaf node. After that the value number is followed. Then the node is followed by repeating offset and key combination.

nonleaf node

leaf node (not the last one)

leaf node (the last leaf node)

datatypes

some of the structs are predefined:

some consts

const int Int(0), Float(1), Char_n(2);
const int Greater(1), NotLess(2), Less(3), NotGreater(4);
const int DataFile(0), IndexFile(1);

node(block)

struct blockInfo {
    int blockNum;               // the block number of the block
    bool dirtyBit;              // 0 -> flase
                                // 1 -> indicate dirty, write back
    blockInfo *next;            // the pointer point to next block 
    fileInfo *file;             // the pointer point to the file, which the block belongs to
    int charNum;                // the number of chars in the block
    char *cBlock;               // the array space for storing the records in the block in buffer
    int iTime;                  // it indicate the age of the block in use 
    int lock;                   // prevent the block from replacing
};

index(key)

struct index_info {
    std::string index_name;     //the name of the index file
    int length;                 //the length of the value
    char type;                  //the type of the value
                                //0---int,1---float,2----char(n)    
    long offset;                //the record offset in the table file
    std::string value;          //the value
    index_info(){}
};