func initDriver() error {
//Allocate environment handle
var out api.SQLHANDLE
in := api.SQLHANDLE(api.SQL_NULL_HANDLE)
ret := api.SQLAllocHandle(api.SQL_HANDLE_ENV, in, &out)
if IsError(ret) {
return NewError("SQLAllocHandle", api.SQLHENV(in))
}
drv.h = api.SQLHENV(out)
drv.Stats.updateHandleCount(api.SQL_HANDLE_ENV, 1)
// will use ODBC v3
ret = api.SQLSetEnvAttr(drv.h, api.SQL_ATTR_ODBC_VERSION,
api.SQLPOINTER(api.SQL_OV_ODBC3), 0)
if IsError(ret) {
defer releaseHandle(drv.h)
return NewError("SQLSetEnvAttr", drv.h)
}
//TODO: find a way to make this attribute changeable at runtime
//Enable connection pooling
ret = api.SQLSetEnvAttr(drv.h, api.SQL_ATTR_CONNECTION_POOLING, api.SQLPOINTER(api.SQL_CP_ONE_PER_HENV), api.SQL_IS_UINTEGER)
if IsError(ret) {
defer releaseHandle(drv.h)
return NewError("SQLSetEnvAttr", drv.h)
}
//Set relaxed connection pool matching
ret = api.SQLSetEnvAttr(drv.h, api.SQL_ATTR_CP_MATCH, api.SQLPOINTER(api.SQL_CP_RELAXED_MATCH), api.SQL_IS_UINTEGER)
if IsError(ret) {
defer releaseHandle(drv.h)
return NewError("SQLSetEnvAttr", drv.h)
}
//TODO: it would be nice if we could call "drv.SetMaxIdleConns(0)" here but from the docs it looks like
//the user must call this function after db.Open
return nil
}
func ToHandleAndType(handle interface{}) (h api.SQLHANDLE, ht api.SQLSMALLINT) {
switch v := handle.(type) {
case api.SQLHENV:
if v == api.SQLHENV(api.SQL_NULL_HANDLE) {
ht = 0
} else {
ht = api.SQL_HANDLE_ENV
}
h = api.SQLHANDLE(v)
case api.SQLHDBC:
ht = api.SQL_HANDLE_DBC
h = api.SQLHANDLE(v)
case api.SQLHSTMT:
ht = api.SQL_HANDLE_STMT
h = api.SQLHANDLE(v)
default:
panic(fmt.Errorf("unexpected handle type %T", v))
}
return h, ht
}
func (d *Driver) Close() error {
// TODO(brainman): who will call (*Driver).Close (to dispose all opened handles)?
h := d.h
d.h = api.SQLHENV(api.SQL_NULL_HENV)
return releaseHandle(h)
}