Development Process

Figure 1 ODBC-based application development process

APIs Involved in the Development Process

Table 1 API description

Function	API
Allocate a handle	SQLAllocHandle is a generic function for allocating a handle. It can replace the following functions: SQLAllocEnv: allocate an environment handle SQLAllocConnect: allocate a connection handle SQLAllocStmt: allocate a statement handle
Set environment attributes	SQLSetEnvAttr
Set connection attributes	SQLSetConnectAttr
Set statement attributes	SQLSetStmtAttr
Connect to a data source	SQLConnect
Bind a buffer to a column in the result set	SQLBindCol
Bind the parameter marker of an SQL statement to a buffer	SQLBindParameter
Return the error message of the last operation	SQLGetDiagRec
Prepare an SQL statement for execution	SQLPrepare
Run a prepared SQL statement	SQLExecute
Run an SQL statement directly	SQLExecDirect
Fetch the next row (or rows) from the result set	SQLFetch
Return data in a column of the result set	SQLGetData
Get the column information from a result set	SQLColAttribute
Disconnect from a data source	SQLDisconnect
Release a handle	SQLFreeHandle is a generic function for releasing a handle. It can replace the following functions: SQLFreeEnv: release an environment handle SQLFreeConnect: release a connection handle SQLFreeStmt: release a statement handle

NOTE

If an execution request (not in a transaction block) received in the database contains multiple statements, the request is packed into a transaction. If one of the statements fails, the entire request will be rolled back.

注意

ODBC is the central layer of the application program and the database. It is responsible for transmitting the SQL instructions issued by the application program to the database, and does not parse the SQL syntax by itself. Therefore, when an SQL statement with confidential information (such as a plaintext password) is written in an application, the confidential information will be exposed in the driver log.