C++使用Sqlite
最近项目中有使用到sqlite处理数据，发现以前最基本的SQL有点把握不住了，就赶紧复习回顾一下。
1.先下载SQLlite官网下载包
https://www.sqlite.org/download.html
SQLite Download Page - Source Code - 我选择的版本号是：version 3.35.5
下载解压完成后，拿到四个文件：
2.添加进我们VS工程
开发环境：VS2013。
添加四个文件到我们的工程：
–编译错误;
错误原因：不该使用预编译头。
解决方法：选中两个源文件-属性-C/C+±预编译头-不使用预编译头
嘿，编译成功
3.demo工程中添加工具类【CSqliteOperator】
实现基本的功能：增删改查战士。
#pragma once
#include #include "stdafx.h"
#include "SqliteOperator.h"
CSqliteOperator::CSqliteOperator()
{
pDB = NULL;
}
CSqliteOperator::~CSqliteOperator()
{
Destory();
}
void CSqliteOperator::Destory()
{
if (pDB)
{
sqlite3_close(pDB);
pDB = NULL;
}
}
int CSqliteOperator::CreateSqlFile(const string& path)
{
return sqlite3_open(path.c_str(), &pDB);
}
int CSqliteOperator::CreateTable(const string& sql)
{
char *szMsg = NULL;
return sqlite3_exec(pDB, sql.c_str(), NULL, NULL, &szMsg);
}
int CSqliteOperator::Open(const string& path)
{
return sqlite3_open(path.c_str(), &pDB);
}
int CSqliteOperator::Insert(const string& sql)
{
if (sql.empty()) return -1;
char* zErrMsg = NULL;
int ret = sqlite3_exec(pDB, sql.c_str(), NULL, NULL, &zErrMsg);
return ret;
}
int CSqliteOperator::Delete(const string& sql)
{
int nCols = 0;
int nRows = 0;
char **azResult = NULL;
char *errMsg = NULL;
return sqlite3_get_table(pDB, sql.c_str(), &azResult, &nRows, &nCols, &errMsg);
}
int CSqliteOperator::Update(const string& sql)
{
char* zErrMsg = NULL;
int ret = sqlite3_exec(pDB, sql.c_str(), NULL, NULL, &zErrMsg);
return ret;
}
int CSqliteOperator::FindCurrentTableMaxKey(const string& tableName, const string& strKey, int& nMaxKey)
{
nMaxKey = -1;
if (tableName.empty() || strKey.empty()) return -1;
string sql = "select * from " + tableName;
int nCol = -1;
int nRow = -1;
int index = -1;
char **azResult = NULL;
char *errMsg = NULL;
int result = sqlite3_get_table(pDB, sql.c_str(), &azResult, &nRow, &nCol, &errMsg);
index = nCol;
//取出最新的，对比穿进去的主键串，就是主键Max值
for (int i = 0; i < nRow; i++)
{
for (int j = 0; j < nCol; j++)
{
string s1 = azResult[j];
string s2 = azResult[index];
if (s1 == strKey)
{
nMaxKey = atoi(azResult[index]);
}
index++;
}
}
return result;
}
int CSqliteOperator::FindAllData(const string& sql, vector<string>& arrKey, vector<vector<string>>& arrValue)
{
if (sql.empty()) return -1;
int nCols = 0;
int nRows = 0;
char **azResult = NULL;
char *errMsg = NULL;
int index = 0;
const int result = sqlite3_get_table(pDB, sql.c_str(), &azResult, &nRows, &nCols, &errMsg);
index = nCols;
arrKey.clear();
arrKey.reserve(nCols);
arrValue.clear();
arrValue.reserve(nRows);
bool bKeyCaptured = false;
for (int i = 0; i < nRows; i++)
{
vector<string> temp;
for (int j = 0; j < nCols; j++)
{
if (!bKeyCaptured)
{
arrKey.push_back(azResult[j]);
}
temp.push_back(azResult[index]);
index++;
}
bKeyCaptured = true;
arrValue.push_back(temp);
}
return result;
}
4.测试用例
4.1列出主要测试函数：标的创建、数据的、增、删、改、查：
/************************************************************************/
/*主键nID，自增属性*/
/************************************************************************/
void CDemoDlg::OnBnClickedButtonCreateTable()
{
const CString path = GetAppPath() + "\\hunter.db";
const CString name = "hunter";
CSqliteOperator operatorr;
if (!PathFileExists(path))
{
int result = operatorr.CreateSqlFile(path.GetString());
if (result != SQLITE_OK)
{
MessageBox("文件创建失败", "温馨提示");
}
else
{
const char *sql = "create table hunter(nID integer primary key autoincrement,name string,age integer,sex integer)";
result = operatorr.CreateTable(sql);
if (result != SQLITE_OK)
{
MessageBox("表创建失败", "温馨提示");
}
else
{
MessageBox("表创建成功", "温馨提示");
}
}
}
else
{
MessageBox("表已存在", "温馨提示");
}
}
/************************************************************************/
/* 先添加DB对象，再添加内存对象，保持同步 */
/************************************************************************/
void CDemoDlg::OnBnClickedButtonAdd()
{
const CString path = GetAppPath() + "\\hunter.db";
const CString name = "hunter";
if (!PathFileExists(path))
{
MessageBox("文件不存在", "温馨提示");
return;
}
CString strName, strAge, strSex;
CHunter hunter;
GetDlgItemText(IDC_EDIT_NAME, strName);
hunter.name = strName;
GetDlgItemText(IDC_EDIT_AGE, strAge);
hunter.age = atoi(strAge);
GetDlgItemText(IDC_EDIT_SEX, strSex);
hunter.sex = atoi(strSex);
if (strName.IsEmpty() || strAge.IsEmpty() || strSex.IsEmpty())
{
MessageBox("数据不健全", "温馨提示");
return;
}
bool bFind = false;
for (auto it : m_arrData)
{
if (it.name == hunter.name &&
it.age == hunter.age &&
it.sex == hunter.sex)
{
bFind = true;
break;
}
}
if (bFind)
{
MessageBox("数据已存在", "温馨提示");
return;
}
CSqliteOperator operatorr;
int result = operatorr.Open(path.GetString());
if (result != SQLITE_OK)
{
MessageBox("文件打开失败", "温馨提示");
return;
}
string strSQL = "insert into hunter(name,age,sex)";
strSQL += "values('";
strSQL += hunter.name;
strSQL += "',";
strSQL += "'";
strSQL += std::to_string(hunter.age);
strSQL += "',";
strSQL += "'";
strSQL += std::to_string(hunter.sex);
strSQL += "',";
CString temp = strSQL.c_str();
temp.TrimRight(",");
temp.Append(")");
strSQL = temp;
result = operatorr.Insert(strSQL);
if (result != SQLITE_OK)
{
MessageBox("插入失败", "温馨提示");
return;
}
int nID = 0;
result = operatorr.FindCurrentTableMaxKey("hunter", "nID", nID);
if (result != SQLITE_OK)
{
MessageBox("查询失败", "温馨提示");
return;
}
if (nID == 0)
{
nID = 1;
}
hunter.nID = nID;
m_arrData.push_back(hunter);
UpdateList();
MessageBox("添加成功", "温馨提示");
}
/************************************************************************/
/* 先删除DB对象，再删除内存对象，保持同步 */
/************************************************************************/
void CDemoDlg::OnBnClickedButtonDelete()
{
const CString path = GetAppPath() + "\\hunter.db";
const CString name = "hunter";
if (!PathFileExists(path))
{
MessageBox("文件不存在", "温馨提示");
return;
}
const int nSel = m_listCtrl.GetSelectionMark();
if (nSel < 0 || nSel >= m_arrData.size())
{
MessageBox("请选择条目", "温馨提示");
return;
}
CSqliteOperator operatorr;
int result = operatorr.Open(path.GetString());
if (result != SQLITE_OK)
{
MessageBox("文件打开失败", "温馨提示");
return;
}
CString tableName = "hunter";
CString strKey = "nID";
const int nID = m_arrData[nSel].nID;
string temp = to_string(nID);
string strSQL = "delete from " + tableName + " where ";
strSQL.append(strKey + " =");
strSQL.append(temp);
result = operatorr.Delete(strSQL);
if (result != SQLITE_OK)
{
MessageBox("文件打开失败", "温馨提示");
return;
}
m_arrData.erase(m_arrData.begin() + nSel);
UpdateList();
MessageBox("删除成功", "温馨提示");
}
/************************************************************************/
/* 先修改DB对象，再修改内存对象，保持同步 */
/************************************************************************/
void CDemoDlg::OnBnClickedButtonModify()
{
const int nSel = m_listCtrl.GetSelectionMark();
if (nSel < 0 || nSel >= m_arrData.size()) return;
const CString path = GetAppPath() + "\\hunter.db";
const CString name = "hunter";
if (!PathFileExists(path))
{
MessageBox("文件不存在", "温馨提示");
return;
}
CString str;
CSqliteOperator operatorr;
int result = operatorr.Open(path.GetString());
if (result != SQLITE_OK)
{
MessageBox("文件打开失败", "温馨提示");
return;
}
const int nID = m_arrData[nSel].nID;
CString newName;
GetDlgItemText(IDC_EDIT_NAME2, newName);
CString newAge;
GetDlgItemText(IDC_EDIT_AGE2, newAge);
CString newSex;
GetDlgItemText(IDC_EDIT_SEX2, newSex);
if (newName.IsEmpty() || newAge.IsEmpty() || newSex.IsEmpty())
{
MessageBox("未设置修改数据", "温馨提示");
return;
}
string strSQL = "update hunter set name =";
strSQL += "'";
strSQL += newName;
strSQL += "',";
strSQL += "age ='";
strSQL += newAge;
strSQL += "',";
strSQL += "sex ='";
strSQL += newSex;
strSQL += "',";
CString ss = strSQL.c_str();
ss.TrimRight(',');
ss.Append(" where nID =");
CString temp;
temp.Format("%d", nID);
ss.Append(temp);
strSQL = ss.GetString();
result = operatorr.Update(strSQL.c_str());
if (result != SQLITE_OK)
{
MessageBox("数据库更新失败", "温馨提示");
return;
}
auto& item = m_arrData[nSel];
item.name = newName;
item.age = atoi(newAge);
item.sex = atoi(newSex);
UpdateList();
MessageBox("修改成功", "温馨提示");
}
void CDemoDlg::OnBnClickedButtonFind()
{
const CString path = GetAppPath() + "\\hunter.db";
const CString name = "hunter";
if (!PathFileExists(path))
{
MessageBox("文件不存在", "温馨提示");
return;
}
CString str;
CSqliteOperator operatorr;
int result = operatorr.Open(path.GetString());
if (result != SQLITE_OK)
{
MessageBox("文件打开失败", "温馨提示");
return;
}
GetDlgItemText(IDC_EDIT_ID, str);
if (str.IsEmpty()) return;
string strSQL = "select * from " + name + " where nID = ";
strSQL += str;
vector<string> arrKey;
vector<vector<string>> arrValue;
result = operatorr.FindAllData(strSQL, arrKey, arrValue);
if (result == SQLITE_OK && !arrKey.empty() && !arrValue.empty())
{
CString temp = arrKey[0].c_str();
temp.Append(": ");
temp.Append(arrValue[0][0].c_str());
temp.Append(",");
CString text = "查询成功: ";
text.Append(temp);
temp = arrKey[1].c_str();
temp.Append(": ");
temp.Append(arrValue[0][1].c_str());
temp.Append(",");
text.Append(temp);
temp = arrKey[2].c_str();
temp.Append(": ");
temp.Append(arrValue[0][2].c_str());
text.Append(temp);
MessageBox(text, "温馨提示");
}
}
Demo链接