What is ODBC?
Open Database Connectivity (ODBC) is a standard API for accessing database management systems (DBMS). It enables applications to communicate with a variety of DBMSs using a uniform set of functions.
Key Concepts
- Driver Manager – Manages the communication between an application and the installed ODBC drivers.
- ODBC Driver – Translates ODBC calls into DBMS‑specific commands.
- Data Source Name (DSN) – A configured alias that contains connection information for a particular database.
- SQL Queries – Standardized queries executed via ODBC functions.
Architecture
The ODBC architecture consists of three layers:
- Application Layer – Your program uses the ODBC API.
- Driver Manager Layer – Handles driver loading, connection pooling, and thread safety.
- Driver Layer – Communicates directly with the DBMS.
Getting Started
Follow these steps to start using ODBC in a C/C++ application on Windows:
// Example: Simple ODBC connection and query (C++)
#include <windows.h>
#include <sql.h>
#include <sqlext.h>
int main() {
SQLHENV hEnv;
SQLHDBC hDbc;
SQLHSTMT hStmt;
SQLRETURN ret;
// Allocate environment handle
ret = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv);
if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) return -1;
// Set ODBC version
SQLSetEnvAttr(hEnv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);
// Allocate connection handle
SQLAllocHandle(SQL_HANDLE_DBC, hEnv, &hDbc);
// Connect using a DSN
ret = SQLConnect(hDbc,
(SQLCHAR *)"MyDSN", SQL_NTS,
(SQLCHAR *)"username", SQL_NTS,
(SQLCHAR *)"password", SQL_NTS);
if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
// handle error
return -1;
}
// Allocate statement handle
SQLAllocHandle(SQL_HANDLE_STMT, hDbc, &hStmt);
// Execute a query
ret = SQLExecDirect(hStmt, (SQLCHAR *)"SELECT TOP 10 * FROM Employees", SQL_NTS);
if (ret == SQL_SUCCESS || ret == SQL_SUCCESS_WITH_INFO) {
// Process results...
}
// Cleanup
SQLFreeHandle(SQL_HANDLE_STMT, hStmt);
SQLDisconnect(hDbc);
SQLFreeHandle(SQL_HANDLE_DBC, hDbc);
SQLFreeHandle(SQL_HANDLE_ENV, hEnv);
return 0;
}