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  • SQLite wrapper

    SQLiteWrapper is a C++ wrapper for SQLite.
    There are some test programs that demonstrate how the SQLite Wrapper classes are used.
    The implementation file
    SQLiteWrapper.cpp
    /*
    SQLiteWrapper.cpp
     
    Copyright (C) 2004 René Nyffenegger
     
    This source code is provided 'as-is', without any express or implied
    warranty. In no event will the author be held liable for any damages
    arising from the use of this software.
     
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
     
    1. The origin of this source code must not be misrepresented; you must not
    claim that you wrote the original source code. If you use this source code
    in a product, an acknowledgment in the product documentation would be
    appreciated but is not required.
     
    2. Altered source versions must be plainly marked as such, and must not be
    misrepresented as being the original source code.
     
    3. This notice may not be removed or altered from any source distribution.
     
    René Nyffenegger rene.nyffenegger@adp-gmbh.ch
     
    */
     
    #include "SQLiteWrapper.h"
    // TODO: raus
    #include <windows.h>
     
    SQLiteWrapper::SQLiteWrapper() : db_(0) {
    }
     
    bool SQLiteWrapper::Open(std::string const& db_file) {
    if (sqlite3_open(db_file.c_str(), &db_) != SQLITE_OK) {
    return false;
    }
    return true;
    }
     
    bool SQLiteWrapper::SelectStmt(std::string const& stmt, ResultTable& res) {
    char *errmsg;
    int ret;
     
    res.reset();
     
    ret = sqlite3_exec(db_, stmt.c_str(), SelectCallback, static_cast<void*> (&res), &errmsg);
     
    if (ret != SQLITE_OK) {
    return false;
    }
    return true;
    // if (ret != SQLITE_OK) {
    // std::cout << stmt << " [" << errmsg << "]" << std::endl;
    // }
    }
     
    // TODO parameter p_col_names
    int SQLiteWrapper::SelectCallback(void *p_data, int num_fields, char **p_fields, char** p_col_names) {
    ResultTable* res = reinterpret_cast<ResultTable*>(p_data);
     
    ResultRecord record;
     
    #ifdef SQLITE_WRAPPER_REPORT_COLUMN_NAMES
    // Hubert Castelain: column names in the first row of res if res is empty
     
    if(res->records_.size()==0) {
    ResultRecord col_names;
     
    for(int i=0; i < num_fields; i++) {
    if(p_fields[i]) col_names.fields_.push_back (p_col_names[i]);
    else
    col_names.fields_.push_back("(null)"); // or what else ?
    }
    res->records_.push_back(col_names);
    }
    #endif
     
    for(int i=0; i < num_fields; i++) {
    // Hubert Castelain: special treatment if null
    if (p_fields[i]) record.fields_.push_back(p_fields[i]);
    else record.fields_.push_back("<null>");
    }
     
    res->records_.push_back(record);
     
    return 0;
    }
     
    SQLiteStatement* SQLiteWrapper::Statement(std::string const& statement) {
    SQLiteStatement* stmt;
    try {
    stmt = new SQLiteStatement(statement, db_);
    return stmt;
    }
    catch (const char* e) {
    return 0;
    }
    }
     
    SQLiteStatement::SQLiteStatement(std::string const& statement, sqlite3* db) {
    if ( sqlite3_prepare(
    db,
    statement.c_str(), // stmt
    -1, // If than zero, then stmt is read up to the first nul terminator
    &stmt_,
    0 // Pointer to unused portion of stmt
    )
    != SQLITE_OK) {
    throw sqlite3_errmsg(db);
    }
     
    if (!stmt_) {
    throw "stmt_ is 0";
    }
    }
     
    SQLiteStatement::~SQLiteStatement() {
    // Hubert Castelain 28/8/2005
    // Prevent the database remaining locked after some statement.
    // syntax: int sqlite3_finalize(sqlite3_stmt *pStmt);
    if(stmt_) sqlite3_finalize(stmt_);
    }
     
    SQLiteStatement::SQLiteStatement() :
    stmt_ (0)
    {
    }
     
    bool SQLiteStatement::Bind(int pos_zero_indexed, std::string const& value) {
    if (sqlite3_bind_text (
    stmt_,
    pos_zero_indexed+1, // Index of wildcard
    value.c_str(),
    value.length(), // length of text
    SQLITE_TRANSIENT // SQLITE_TRANSIENT: SQLite makes its own copy
    )
    != SQLITE_OK) {
    return false;
    }
    return true;
    }
     
    bool SQLiteStatement::Bind(int pos_zero_indexed, double value) {
    if (sqlite3_bind_double(
    stmt_,
    pos_zero_indexed+1, // Index of wildcard
    value
    )
    != SQLITE_OK) {
    return false;
    }
    return true;
    }
     
    bool SQLiteStatement::Bind(int pos_zero_indexed, int value) {
    if (sqlite3_bind_int(
    stmt_,
    pos_zero_indexed+1, // Index of wildcard
    value
    )
    != SQLITE_OK) {
    return false;
    }
    return true;
    }
     
    bool SQLiteStatement::BindNull(int pos_zero_indexed) {
    if (sqlite3_bind_null(
    stmt_,
    pos_zero_indexed+1 // Index of wildcard
    )
    != SQLITE_OK) {
    return false;
    }
    return true;
    }
     
    bool SQLiteStatement::Execute() {
    int rc = sqlite3_step(stmt_);
    if (rc == SQLITE_BUSY) {
    ::MessageBox(0, "SQLITE_BUSY", 0, 0);
    return false;
    }
    if (rc == SQLITE_ERROR) {
    ::MessageBox(0, "SQLITE_ERROR", 0, 0);
    return false;
    }
    if (rc == SQLITE_MISUSE) {
    ::MessageBox(0, "SQLITE_ERROR", 0, 0);
    return false;
    }
    if (rc != SQLITE_DONE) {
    //sqlite3_reset(stmt_);
    return false;
    }
    sqlite3_reset(stmt_);
    return true;
    }
     
    SQLiteStatement::dataType SQLiteStatement::DataType(int pos_zero_indexed) {
    return dataType(sqlite3_column_type(stmt_, pos_zero_indexed));
    }
     
    int SQLiteStatement::ValueInt(int pos_zero_indexed) {
    return sqlite3_column_int(stmt_, pos_zero_indexed);
    }
     
    std::string SQLiteStatement::ValueString(int pos_zero_indexed) {
    return std::string(reinterpret_cast<const char*>(sqlite3_column_text(stmt_, pos_zero_indexed)));
    }
     
    bool SQLiteStatement::RestartSelect() {
    sqlite3_reset(stmt_);
    return true;
    }
     
    bool SQLiteStatement::Reset() {
    int rc = sqlite3_step(stmt_);
     
    sqlite3_reset(stmt_);
     
    if (rc == SQLITE_ROW) return true;
    return false;
    }
     
    bool SQLiteStatement::NextRow() {
    int rc = sqlite3_step(stmt_);
     
    if (rc == SQLITE_ROW ) {
    return true;
    }
    if (rc == SQLITE_DONE ) {
    sqlite3_reset(stmt_);
    return false;
    }
    else if (rc == SQLITE_MISUSE) {
    ::MessageBox(0, "SQLiteStatement::NextRow SQLITE_MISUSE", 0, 0);
    }
    else if (rc == SQLITE_BUSY ) {
    ::MessageBox(0, "SQLiteStatement::NextRow SQLITE_BUSY", 0, 0);
    }
    else if (rc == SQLITE_ERROR ) {
    ::MessageBox(0, "SQLiteStatement::NextRow SQLITE_ERROR", 0, 0);
    }
    return false;
    }
     
    bool SQLiteWrapper::DirectStatement(std::string const& stmt) {
    char *errmsg;
    int ret;
     
    ret = sqlite3_exec(db_, stmt.c_str(), 0, 0, &errmsg);
     
    if(ret != SQLITE_OK) {
    return false;
    }
    return true;
     
    //if(ret != SQLITE_OK) {
    // std::cout << stmt << " [" << errmsg << "]" << std::endl;
    //}
    }
     
    std::string SQLiteWrapper::LastError() {
    return sqlite3_errmsg(db_);
    }
     
    bool SQLiteWrapper::Begin() {
    return DirectStatement("begin");
    }
     
    bool SQLiteWrapper::Commit() {
    return DirectStatement("commit");
    }
     
    bool SQLiteWrapper::Rollback() {
    return DirectStatement("rollback");
    }
    The header file
    SQLiteWrapper.h
    /*
    SQLiteWrapper.h
     
    Copyright (C) 2004 René Nyffenegger
     
    This source code is provided 'as-is', without any express or implied
    warranty. In no event will the author be held liable for any damages
    arising from the use of this software.
     
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
     
    1. The origin of this source code must not be misrepresented; you must not
    claim that you wrote the original source code. If you use this source code
    in a product, an acknowledgment in the product documentation would be
    appreciated but is not required.
     
    2. Altered source versions must be plainly marked as such, and must not be
    misrepresented as being the original source code.
     
    3. This notice may not be removed or altered from any source distribution.
     
    René Nyffenegger rene.nyffenegger@adp-gmbh.ch
    */
     
    #ifndef SQLITE_WRAPPER_H__
    #define SQLITE_WRAPPER_H__
     
    #include <string>
    #include <vector>
     
    #include "sqlite3.h"
     
    class SQLiteStatement {
    private:
    // SQLiteStatement's ctor only to be called by SQLiteWrapper
    friend class SQLiteWrapper;
    SQLiteStatement(std::string const& statement, sqlite3* db);
     
    public:
    SQLiteStatement();
     
    enum dataType {
    INT = SQLITE_INTEGER,
    FLT = SQLITE_FLOAT ,
    TXT = SQLITE_TEXT ,
    BLB = SQLITE_BLOB ,
    NUL = SQLITE_NULL ,
    };
     
    dataType DataType(int pos_zero_indexed);
     
    int ValueInt (int pos_zero_indexed);
    std::string ValueString(int pos_zero_indexed);
     
    // SQLiteStatement(const SQLiteStatement&);
    ~SQLiteStatement();
     
    //SQLiteStatement& operator=(SQLiteStatement const&);
     
    bool Bind (int pos_zero_indexed, std::string const& value);
    bool Bind (int pos_zero_indexed, double value);
    bool Bind (int pos_zero_indexed, int value);
    bool BindNull(int pos_zero_indexed);
     
    bool Execute();
     
    bool NextRow();
     
    /* Call Reset if not depending on the NextRow cleaning up.
    For example for select count(*) statements*/
    bool Reset();
     
    bool RestartSelect();
     
    private:
    //void DecreaseRefCounter();
     
    //int* ref_counter_; // not yet used...
    sqlite3_stmt* stmt_;
    };
     
    class SQLiteWrapper {
    public:
    SQLiteWrapper();
     
    bool Open(std::string const& db_file);
     
    class ResultRecord {
    public:
    std::vector<std::string> fields_;
    };
     
    class ResultTable {
    friend class SQLiteWrapper;
    public:
    ResultTable() : ptr_cur_record_(0) {}
     
    std::vector<ResultRecord> records_;
     
    ResultRecord* next() {
    if (ptr_cur_record_ < records_.size()) {
    return &(records_[ptr_cur_record_++]);
    }
    return 0;
    }
     
    private:
    void reset() {
    records_.clear();
    ptr_cur_record_=0;
    }
     
    private:
    unsigned int ptr_cur_record_;
    };
     
    bool SelectStmt (std::string const& stmt, ResultTable& res);
    bool DirectStatement (std::string const& stmt);
    SQLiteStatement* Statement(std::string const& stmt);
     
    std::string LastError();
     
    // Transaction related
    bool Begin ();
    bool Commit ();
    bool Rollback();
     
    private:
     
    static int SelectCallback(void *p_data, int num_fields, char **p_fields, char **p_col_names);
     
    sqlite3* db_;
    };
     
    #endif
    Test cases
    Test 1: creates a database and a table.
    Test 2: inserts a record into the table without binding the value parameters.
    Test 3: inserts two records into the table with binding the value parameters.
    Test 4: selects * from the table and returns the selected values to the console.
    Links
    Joel on software reader is an application I wrote that uses this wrapper.
     
     
     
     
    本地测试
    /* SQLiteWrapper sqlite;
    if (sqlite.Open("SQLiteWrapper.db"))
    {
    MessageBox(0,"成功打开数据库","提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    }
    else
    {
    MessageBox(0,"打开或创建数据库失败","提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    }
     
    if(sqlite.DirectStatement("create table File_list(id text,F_name text,Ex_name text,Path_name text,F_size text,C_time text,X_time text,F_time text,F_Con BLOB );"))
    {
    MessageBox(0,"创建File_list成功","提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    }
    else
    {
    MessageBox(0,"创建File_list失败","提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    }
     
    if(sqlite.DirectStatement("insert into File_list values('1','2','中国','4','English','6','7','8','9')"))
    {
     
    MessageBox(0,"插入成功","提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    }
    else
    {
    MessageBox(0,"插入失败","提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    }
     
    SQLiteStatement* stmt=sqlite.Statement("select * from File_list");
    int j=0;
     
    while(stmt->NextRow()){
    //MessageBox(0,stmt->DataType (0),"提示",MB_ICONEXCLAMATION|MB_OKCANCEL );
    MessageBox(0,(stmt->ValueString(j)).c_str(),"提示",MB_ICONEXCLAMATION );
    //std::cout<<stmt->DataType(0)<<" - "<<stmt->DataType (1) <<" | "<<
    //stmt->ValueString(0)<<" - "<<stmt->ValueString(1)<<std::endl;
    j++;
    }*/
     
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  • 原文地址:https://www.cnblogs.com/blogpro/p/11426873.html
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