C ++ Class Library: OTL connects to the MySQL ODBC database (insert, update, select) and otlodbc

C ++ Class Library: OTL connects to the MySQL ODBC database (insert, update, select) and otlodbc

I. Introduction

OTL is a pure C ++ universal database connection template library, can support a variety of popular databases, such as Oracle, Sybase, MySQL, PostgreSQL, EnterpriseDB, SQLite, ms access, Firebird and so on. it is a cross-platform class library that can be used in MS Windows, Linux/Unix/Mac OS X.

OTL is easy to use, as long as the header file contains: # include "otlv4.h". In fact, the entire OTL is a. H file, which is very convenient to use.

My download space:

Code: http://download.csdn.net/detail/u013354805/9057229

Document: http://download.csdn.net/detail/u013354805/9057243

Case: http://download.csdn.net/detail/u013354805/9057273

Official: http://otl.sourceforge.net/

Ii. Usage:

1. First, specify the database type to be connected. OTL uses a macro definition to specify the database type to be connected. OTL initializes the database connection environment according to the macro definition.

Related macro definition list: http://otl.sourceforge.net/otl3_compile.htm

For example, # define OTL_ODBC_MYSQL indicates connecting to the ODBC MySQL database.

2. case:

1) Specify the database type to connect:

# Define OTL_ODBC_MYSQL // specify the connected database type

2) import the OTL 4 header file

#include <otlv4.h> // include the OTL 4 header file

3) define a database instance:

Otl_connect db; // defines the database instance

4) initialize the ODBC environment:

otl_connect::otl_initialize();

5) connect to ODBC:

db.rlogon("UID=scott;PWD=tiger;DSN=mysql"); // connect to ODBC

6). delete a table:

otl_cursor::direct_exec   (    db,    "drop table test_tab",    otl_exception::disabled // disable OTL exceptions   ); // drop table

7). Create a table:

otl_cursor::direct_exec   (    db,    "create table test_tab(f1 int, f2 varchar(30))"    );  // create table

8) Insert statement:

// insert rows into table void insert(){  otl_stream o(1, // buffer size should be == 1 always on INSERT              "insert into test_tab values(:f1<int>,:f2<char[31]>)",                  // SQL statement              db // connect object             ); char tmp[32]; for(int i=1;i<=100;++i) {  sprintf(tmp,"Name%d",i);  o<<i<<tmp; }}

9). Update statement:

// update row data into tablevoid update(const int af1){  otl_stream o(1, // buffer size should be == 1 always on UPDATE  "UPDATE test_tab "  "   SET f2=:f2<char[31]> "  " WHERE f1=:f1<int>",  // UPDATE statement  db // connect object ); o<<"Name changed"<<af1; o<<otl_null()<<af1+1; // set f2 to NULL}

10). Select statement:

// MyODBC does not allow any input bind variables in the WHERE clause// in a SELECT statement.// Therefore, the SELECT statement has to be generated literally.void select(const int af1){  char stmbuf[1024]; sprintf(stmbuf,         "select * from test_tab where f1>=%d and f1<=%d*2",         af1,         af1        ); otl_stream i(50, // buffer size may be > 1              stmbuf, // SELECT statement              db // connect object             );    // create select stream  int f1; char f2[31]; while(!i.eof()) { // while not end-of-data  i>>f1;  cout<<"f1="<<f1<<", f2=";  i>>f2;  if(i.is_null())   cout<<"NULL";  else   cout<<f2;  cout<<endl; }}

11). Disconnect ODBC:

db.logoff(); // disconnect from ODBC

12). case:

int main(){ otl_connect::otl_initialize(); // initialize ODBC environment try {  db.rlogon("UID=scott;PWD=tiger;DSN=mysql"); // connect to ODBC  //  db.rlogon("scott/tiger@mysql"); // connect to ODBC, alternative format                                     // of connect string   otl_cursor::direct_exec   (    db,    "drop table test_tab",    otl_exception::disabled // disable OTL exceptions   ); // drop table  otl_cursor::direct_exec   (    db,    "create table test_tab(f1 int, f2 varchar(30))"    );  // create table  insert(); // insert records into the table  update(10); // update records in the table  select(8); // select records from the table } catch(otl_exception& p) { // intercept OTL exceptions  cerr<<p.msg<<endl; // print out error message  cerr<<p.stm_text<<endl; // print out SQL that caused the error  cerr<<p.sqlstate<<endl; // print out SQLSTATE message  cerr<<p.var_info<<endl; // print out the variable that caused the error } db.logoff(); // disconnect from ODBC return 0;}

13). Running result:

Outputf1=8, f2=Name8f1=9, f2=Name9f1=10, f2=Name changedf1=11, f2=NULLf1=12, f2=Name12f1=13, f2=Name13f1=14, f2=Name14f1=15, f2=Name15f1=16, f2=Name16

Copyright Disclaimer: This article is an original article by the blogger and cannot be reproduced without the permission of the blogger.