教你使用微软小型数据库esent

#include <esent.h>
#include <Windows.h>
#include <iostream>
#pragma comment (lib, "esent.lib")
using namespace std;
JET_ERR WriteTest(JET_SESID& sessionID,JET_DBID& dbID)
{
    JET_TABLEID iTableID;
    JET_COLUMNID iColumnId[2];//本例子中表有两列
    JET_ERR err = JetOpenTable(sessionID, dbID, "esenttable", NULL, 0, 0, &iTableID);//获取iTableID,插入时需要指定iTableID
    if (err!=JET_errSuccess)
    {
        return err;
    }

    //以下获取列的ID： iColumnId ***************************************************************
    JET_COLUMNDEF columnInfo = {};
    columnInfo.cbStruct = sizeof(columnInfo);
    err=JetGetColumnInfo(sessionID, dbID, "esenttable", "name", &columnInfo, columnInfo.cbStruct, JET_ColInfo);
    if (err!=JET_errSuccess)
    {
        return err;
    }

    iColumnId[0] = columnInfo.columnid;//获取iColumnId
    ZeroMemory(&columnInfo,sizeof(columnInfo));
    columnInfo.cbStruct = sizeof(columnInfo);
    err=JetGetColumnInfo(sessionID, dbID, "esenttable", "age", &columnInfo, columnInfo.cbStruct, JET_ColInfo);
    if (err!=JET_errSuccess)
    {
        return err;
    }
    iColumnId[1] = columnInfo.columnid;//获取iColumnId
    //获取iColumnId 完毕***************************************************************

    //以下填充要插入的值表有两列第一列为name 第二列为age
    JET_SETCOLUMN *setColumn = new JET_SETCOLUMN[2];
    ZeroMemory(setColumn, sizeof(JET_SETCOLUMN)*2);
    setColumn[0].columnid = iColumnId[0];//列的id
    setColumn[0].pvData = "zhangpeng_linux";//列的值，类型为char*
    setColumn[0].cbData = strlen("zhangpeng_linux");//值的长度
    setColumn[0].err = JET_errSuccess;

    int age=25;
    setColumn[1].columnid = iColumnId[1];//列的id
    setColumn[1].pvData = (char*)&age;//列的值，类型为char*
    setColumn[1].cbData =sizeof(age);//值的长度
    setColumn[1].err = JET_errSuccess;

    err = JetBeginTransaction(sessionID);
    if(JET_errSuccess != err)
    {
        JetCloseTable(sessionID, iTableID);
        delete[] setColumn;
        return err;
    }
    err = JetPrepareUpdate(sessionID, iTableID, JET_prepInsert);
    if (JET_errSuccess != err)
    {
        JetRollback(sessionID, 0);
        JetCloseTable(sessionID, iTableID);
        delete[] setColumn;
        return err;
    }
    //这里第三个参数为JET_SETCOLUMN结构指针
    //第四个参数为第三个参数中JET_SETCOLUMN结构的个数
    err = JetSetColumns(sessionID, iTableID, setColumn, 2);
    if (JET_errSuccess != err)
    {
        JetRollback(sessionID, 0);
        JetCloseTable(sessionID, iTableID);
        delete[] setColumn;
        return err;
    }
    //当函数JetSetColumns成功执行后，不代表每列数据都成功插入，需要对检查 //JET_SETCOLUMN结构中的err字段，确保每一列都成功插入
    for (int i = 0; i < 2; i++)
    {
        if (JET_errSuccess != setColumn[i].err)
        {
            JetRollback(sessionID, 0);
            JetCloseTable(sessionID, iTableID);
            delete[] setColumn;
            return setColumn[i].err;
        }
    }

    delete[] setColumn;
    //后三个字段不需要，填入0即可
    err = JetUpdate(sessionID, iTableID, 0, 0, 0);
    if (JET_errSuccess != err)
    {
        JetRollback(sessionID, 0);
        JetCloseTable(sessionID, iTableID);
        return err;
    }

err = JetCommitTransaction(sessionID, 0);
JetCloseTable(sessionID, iTableID);

return err;
}

JET_ERR ReadTest(JET_SESID& sessionID,JET_DBID& dbID)
{
    JET_TABLEID iTableID;
    JET_COLUMNID iColumnId[2];//本例子中表有两列
    JET_ERR err = JetOpenTable(sessionID, dbID, "esenttable", NULL, 0, 0, &iTableID);//获取iTableID
    if (err!=JET_errSuccess)
    {
        return err;
    }
    //以下获取列的ID： iColumnId
    JET_COLUMNDEF columnInfo = {};
    columnInfo.cbStruct = sizeof(columnInfo);
    err=JetGetColumnInfo(sessionID, dbID, "esenttable", "name", &columnInfo, columnInfo.cbStruct, JET_ColInfo);
    if (err!=JET_errSuccess)
    {
        return err;
    }

    char buffer[1024] = { 0 };
    int iLen = sizeof(buffer);
    int age=-1;
    unsigned long nReadBytes=0;
    for(err = JetMove(sessionID, iTableID, JET_MoveFirst, 0);JET_errSuccess == err;err = JetMove(sessionID, iTableID, JET_MoveNext, 0))