SQLite

Connecting to a database

Transaction isolation levels

Working with Long or Lob(CLob, BLob) data

Returning output parameters

Cancelling queries

Connection, command, parameter and field options

Getting native SQLite API

Getting native SQLite connection related handles

Getting native SQLite command related handles

Error handling

Special header files - Compile time

Connecting to a database

To connect to a database you should create a connection object and then connect it. A connection object is represented by SAConnection class. After the connection is created you need to connect it to SQLite server using SAConnection::Connect method

void Connect( const SAString &sDBString, const SAString &sUserID, const SAString &sPassword, SAClient_t eSAClient = SA_Client_NotSpecified );

with the following parameters:

sDBString.   A string containing a valid SQLite database file path.
sUserID.    This parameter isn't used SQLAPI++ with SQLite.
sPassword.   This parameter isn't used SQLAPI++ with SQLite.
eSAClient.    Optional. One of the following values from SAClient_t enum:

• SA_SQLite_Client    SQLite client.
• SA_Client_NotSpecified     Used by default if eSAClientparameter is omitted.  You can use this default value only if you have call SAConnection::setClient method with SA_SQLite_Client constant before.

The SQLAPI++ Library requires libsqlite version 3.x or higher.

For more details see How To - Connecting to databases, SAConnection object, SAConnection::Connect.

Transaction isolation levels

SQL-92 defines four isolation levels, all of which are supported by SQLAPI++ by  SAConnection::setIsolationLevel method. But SQLAPI++ do nothing with this method for SQLite.

Working with Long or Lob(CLob, BLob) data

SQLAPI++ supports four types for working with Long or Lob(CLob, BLob) data:

Name	C enum constant
LongBinary	SA_dtLongBinary
LongChar	SA_dtLongChar
BLob (Binary Large object)	SA_dtBLob
CLob (Character Large object)	SA_dtCLob

The table below shows how SQLAPI++ data types correspond with servers original data types:

SA_dtLongBinary = > SQLITE_BLOB
SA_dtLongChar = > SQLITE_TEXT
SA_dtBLob  = > SQLITE_BLOB
SA_dtCLob  => SQLITE_TEXT

For more details see How To - Working with Long or Lob(CLob, BLob) data

Returning output parameters

SQLAPI++ doesn't support SQLite functions and does not support returning output parameters.

Cancelling queries

Using SACommand::Cancel method you can cancel the following types of processing on a statement:

• A function running asynchronously on the statement.
  
• A function running on the statement on another thread.

SQLAPI++ calls sqlite3_interrupt function to cancel a query. To get more details see sqlite3_interrupt function description in SQLite documentation.

For more details see SACommand::Cancel.

Connection, command, parameter and field options

Getting native SQLite API

You can call client specific API functions which are not directly supported by SQLAPI++ Library. SAConnection::NativeAPI method returns a pointer to the set of native API functions available for SQLite. To use the database API directly you have to downcast this saAPI pointer to the appropriate type and use its implementation-specific members. The following table shows what type cast you have to make and what additional header file you have to include to work with SQLite API.

Type casting	Additional include file
Cast the result to class sl3API: saAPI *pResult = con.NativeAPI(); sl3API *p_sl3API = (sl3API *)pResult;	#include <sl3API.h>

To get more information about DBMS API functions see this DBMS specific documentation. 

For more details see SAConnection::NativeAPI.

Getting native SQLite connection related handles

You have to use native API handles when you want to call specific SQLite API functions which are not directly supported by the Library. API functions usually need to receive one or more active handles as a parameter(s). SAConnection::NativeHandles method returns a pointer to the set of native API connection related handles. To use API handles directly you have to downcast saConnectionHandles pointer to the appropriate type and use its implementation-specific members. The following table shows what type cast you have to make and what additional header file you have to include to work with specific SQLite API.

Type casting

Cast the result to class sl3ConnectionHandles: #include <sl3API.h> saConnectionHandles *pResult = con.NativeHandles(); sl3ConnectionHandles *p_sl3CH =                                 (sl3ConnectionHandles *)pResult; Available handles: sqlite3 *pDb;

To get more information about DBMS API functions and handles see this DBMS specific documentation. 

For more details see SAConnection::NativeHandles.

Getting native SQLite command related handles

You have to use native API handles when you want to call specific SQLite API functions which are not directly supported by the Library. API functions usually need to receive one or more active handles as a parameter(s). SACommand::NativeHandles method returns a pointer to the set of native API command related handles. To use API handles directly you have to downcast saCommandHandles pointer to the appropriate type and use its implementation-specific members. The following table shows what type cast you have to make and what additional header file you have to include to work with specific SQLite API.

Type casting

Cast the result to class sl3CommandHandles: #include <sl3API.h> saCommandHandles *pResult = cmd.NativeHandles(); sl3CommandHandles *p_sl3CH =                                 (sl3CommandHandles *)pResult; Available handles: sqlite3_stmt *pStmt;

To get more information about DBMS API functions and handles see this DBMS specific documentation. 

For more details see SACommand::NativeHandles.

Error handling

When an error occurs inside SQLAPI++ Library it throws an exception of type SAException. SAException::ErrPos method gets an error position in SQL statement. In SQLite server SAException::ErrPos method returns -1 because SQLite does not support this function.

For more details see How To - Error handling, SAException object.

Special header files - Compile time

The header files are in the include subdirectory of SQLAPI++ distributions:
#include <SQLAPI.h> - main header, should be used whenever SQLAPI++ is used.
#include <sl3API.h> - SQLite , should be included if direct libsqlite calls are required.

For more details see Online Documentation - Instructions for Compiling and Linking Applications with SQLAPI++ 

Problems and Questions

If you haven't found the answer to you questions or have some problems on using the Library, please, send e-mail to howto@sqlapi.com.