1 C Development Environment

Considerations for linking without an ODBC driver manager

Applications to be used solely with TimesTen can link specifically with either the TimesTen ODBC direct driver or the ODBC client driver, without a driver manager. This avoids the performance overhead of a driver manager and is the simplest way to access TimesTen. However, developers of applications linked without a driver manager should be aware of the following issues.

• The application can connect only to a DSN (data source name) that uses the driver with which it is linked. It cannot connect to a database of any other vendor, nor can it connect to a TimesTen DSN of a different TimesTen driver. (A DSN is a logical name that identifies a TimesTen database and the set of connection attributes used for connecting to the database.)

• Windows ODBC tracing is not available.

• The ODBC cursor library is not available.

• Applications cannot use ODBC functions that are usually implemented by a driver manager, such as SQLDataSources and SQLDrivers.

• Applications that use SQLCancel to close a cursor instead of SQLFreeStmt(..., SQL_CLOSE) receive a return code of SQL_SUCCESS_WITH_INFO and a SQL state of 01S05. This warning is intended to be used by the driver manager to manage its internal state. Applications should treat this warning as success.

Considerations for linking with an ODBC driver manager

Applications that link with the ODBC driver manager can connect to any DSN that references an ODBC driver and can even connect simultaneously to multiple DSNs that use different ODBC drivers. Note, however, that driver managers are not available by default on most non-Windows platforms. In addition, using a driver manager may add significant synchronization overhead to every ODBC function call and has the following limitations:

• The TimesTen option TT_PREFETCH_COUNT cannot be used with applications that link with a driver manager. For more information on using TT_PREFETCH_COUNT, see "Prefetching multiple rows of data".

• Applications cannot set or reset the TimesTen-specific TT_PREFETCH_CLOSE connection option. For more information about using the TT_PREFETCH_CLOSE connection option, see "Optimizing query performance".

• Transaction Log API (XLA) calls cannot be used when applications are linked with a driver manager.

• The ODBC C types SQL_C_BIGINT, SQL_C_TINYINT, and SQL_C_WCHAR are not supported for an application linked with a driver manager when used with TimesTen. You cannot call methods that have any of these types in their signatures.

• The driver manager does not support LOB locator APIs or LOB data types, which are not part of the ODBC standard. However, you can use the LOB simple data interface or piecewise data interface as documented in "Working with LOBs".

Compiling and linking applications on Windows

To compile TimesTen applications on Windows, you are not required to specify the location of the ODBC include files. These files are included with Microsoft Visual C++. However, to use TimesTen features you must indicate the location of the TimesTen include files in the /I compiler option setting. (See "TimesTen include files".)

Link the appropriate libraries, as follows:

• Directly link to the driver manager: odbc32.lib

  Note that odbc32.lib is for 64-bit systems too.

• Directly link to TimesTen:

  • For direct mode: tten181.lib and ttdv181.lib

  • For client/server mode: ttclient181.lib

The Makefile in Example 1-1 shows how to build a TimesTen application on Windows systems. This example assumes that timesten_home\install\lib has already been added to the LIB environment variable (which is accomplished when you execute ttenv.bat).

CFLAGS = "/Itimesten_home\install\include"
LIBSDM = ODBC32.LIB
LIBS = tten181.lib ttdv181.lib
LIBSDEBUG = tten181d.lib ttdv181d.lib
LIBSCS = ttclient181.lib

# Link with the ODBC driver manager
appldm.exe:appl.obj
           $(CC) /Feappldm.exe appl.obj $(LIBSDM)

# Link directly with the TimesTen
# ODBC production driver
appl.exe:appl.obj
         $(CC) /Feappl.exe appl.obj\
         $(LIBS)

# Link directly with the TimesTen
# ODBC debug driver
appldebug.exe:appl.obj
              $(CC) /Feappldebug.exe appl.obj\
              $(LIBSDEBUG)

# Link directly with the TimesTen
# ODBC client driver
applcs.exe:appl.obj
           $(CC) /Feapplcs.exe appl.obj\
           $(LIBSCS)

Compiling and linking applications on Linux or UNIX

On Linux or UNIX platforms:

• Compile TimesTen applications using the TimesTen header files in the include directory of the TimesTen installation.

• Link with the TimesTen ODBC direct driver or client driver, each of which is provided as a shared library.

On Linux or UNIX, applications using the SQL_C_ULONG, SQL_C_SLONG, SQL_C_USHORT or SQL_C_SSHORT ODBC data types must specify the TT_USE_ALL_TYPES preprocessor option while compiling. This is typically done using the -DTT_USE_ALL_TYPES C compiler option.

To use the TimesTen include files if you are using TimesTen features, add the following to the C compiler command, where timesten_home/install is a symbolic link to installation_dir, the TimesTen installation directory. (See "TimesTen include files".)

-Itimesten_home/install/include

To link with the TimesTen ODBC direct driver, add the following to the link command for the libtten.so library:

-Ltimesten_home/install/lib -ltten

The -L option tells the linker to search the TimesTen lib directory for library files. The -ltten option links in the TimesTen ODBC direct driver.

To link with the TimesTen ODBC client driver, add the following to the link command for the libttclient.so library:

-Ltimesten_home/install/lib -lttclient

On AIX, when linking applications with the TimesTen ODBC client driver, the C++ runtime library must be included in the link command (because the client driver is written in C++ and AIX does not link it automatically) and must follow the client driver:

-Ltimesten_home/install/lib -lttclient -lC_r

You can use Makefiles in subdirectories under the Quick Start sample_code directory (see "TimesTen Quick Start and sample applications"), or you can use Example 1-2 to guide you in creating your own Makefile.

CFLAGS = -Itimesten_home/install/include
LIBS = -Ltimesten_home/install/lib -ltten
LIBSDEBUG = -Ltimesten_home/install/lib -lttenD
LIBSCS = -Ltimesten_home/install/lib -lttclient

# Link directly with the TimesTen
# ODBC production driver
appl:appl.o
     $(CC) -o appl appl.o $(LIBS)

# Link directly with the TimesTen ODBC debug driver
appldebug:appl.o
     $(CC) -o appldebug appl.o $(LIBSDEBUG)

# Link directly with the TimesTen client driver
applcs:appl.o
     $(CC) -o applcs appl.o $(LIBSCS)