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Server Specific Guide

SQLite

SQLAPI++ allows to work with a number of SQL database servers. It provides common mechanisms to access database, and as a general rule they work for any database server. But each server has some specific features which a developer has to know in order to leverage server's unique features and avoid potential errors.

This page collects all specific information that concerns working with SQLite server using SQLAPI++ Library. Full information about using SQLAPI++ see in How To and Online Documentation.

Available topics:

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

A server specific option can relate to a connection, command,  parameter or field. We recommend you specify each option in an appropriate object, although it is possible to specify them in the parental object as well. In that case the option affects all the child objects.

A connection related option must be specified in a  SAConnection object.

A command related option may be specified in either SAConnection object or SACommand object. If it is specified in SAConnection object it affects all the commands on that connection.

A parameter related option may be specified in SAConnection object, SACommand object or SAParam object. If it is specified in SAConnection object it affects all the commands and therefore all the parameters on that connection. If it is specified in SACommand object it affects all the parameters on that command.

A field related option may be specified in SAConnection object, SACommand object or SAField object. If it is specified in SAConnection object it affects all the commands and therefore all the fields on that connection. If it is specified in SACommand object it affects all the fields on that command.

Specific options for SQLite:

Option name / Scope 

Description

SQLITE.LIBS

Connection related. Should be specified before the first connection is made.
Forces SQLAPI++ Library to use specified SQLite client library.

Valid values : Any valid SQLite client library name list. Names separated by ';' on Windows or ':' on other OS.
Default value: Windows - "sqlite3.dll", Linux -  "libsqlite3.so".

BusyTimeout

Connection related. Should be specified before connection is made.

Sets a busy handler that sleeps for a specified amount of time when a table is locked. For more information see SQLite documentation.

Valid values:  any numeric string represents busy timeout (milliseconds).
Default value: empty.

SQLiteVFSName

Connection related. Should be specified before connection is made.

Sets sqlite3_open_v2() interface VFS module name. For more information see SQLite documentation.

Valid values:  any string represents VFS module name.
Default value: empty.

SQLiteVFSFlags

Connection related. Should be specified before connection is made.

Sets sqlite3_open_v2() interface VFS flags. For more information see SQLite documentation.

Valid values:  any numeric string represents VFS flags.
Default value: empty.

SQLiteDateTypes

Connection related.

Sets a comma separated list of database field types those should be interpreted as a datetime fields.

Valid values:  any suitable data type list.
Default value: "DATE,DATETIME,TIME,TIMESTAMP".

SQLiteDateValueType

Connection or command related.

Sets a program type of the SA_dtDateTime parameters.

Valid values:  "TEXT" - the datetime values formatted into "YYYY-MM-DD HH:MM:SS.SSS" strings, "DOUBLE" - the datetime vlaue is the Julian Day (JD) number expressed as a floating point value.
Default value: "TEXT".

SQLiteTransactionType

Connection related.

Sets SQLite transaction type.

Valid values:  "EXCLUSIVE", "IMMEDIATE", "DEFFERED" (default).
Default value: empty.

For more details see SAConnection::setOption, SACommand::setOption, SAField::setOption, SAParam::setOption.


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.