ogrsqlitetablelayer.cpp

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

            nSRSId = atoi(PQgetvalue(hResult,0,0));
        }

        poDS->SoftCommit();
    }
#endif

    return OGRSQLiteLayer::GetSpatialRef();
}

/************************************************************************/
/*                            CreateField()                             */
/************************************************************************/

OGRErr OGRSQLiteTableLayer::CreateField( OGRFieldDefn *poFieldIn, 
                                         int bApproxOK )

{
    char                szFieldType[256];
    OGRFieldDefn        oField( poFieldIn );

    ResetReading();

/* -------------------------------------------------------------------- */
/*      Do we want to "launder" the column names into Postgres          */
/*      friendly format?                                                */
/* -------------------------------------------------------------------- */
    if( bLaunderColumnNames )
    {
        char    *pszSafeName = poDS->LaunderName( oField.GetNameRef() );

        oField.SetName( pszSafeName );
        CPLFree( pszSafeName );
    }
    
/* -------------------------------------------------------------------- */
/*      Work out the PostgreSQL type.                                   */
/* -------------------------------------------------------------------- */
    if( oField.GetType() == OFTInteger )
    {
        strcpy( szFieldType, "INTEGER" );
    }
    else if( oField.GetType() == OFTReal )
    {
        strcpy( szFieldType, "FLOAT" );
    }
    else
    {
        strcpy( szFieldType, "VARCHAR" );
    }

/* -------------------------------------------------------------------- */
/*      How much space do we need for the list of fields.               */
/* -------------------------------------------------------------------- */
    int iField, nFieldListLen = 100;
    char *pszOldFieldList, *pszNewFieldList;

    for( iField = 0; iField < poFeatureDefn->GetFieldCount(); iField++ )
    {
        nFieldListLen += 
            strlen(poFeatureDefn->GetFieldDefn(iField)->GetNameRef()) + 50;
    }

    nFieldListLen += strlen( oField.GetNameRef() );

    pszOldFieldList = (char *) CPLCalloc(1,nFieldListLen);
    pszNewFieldList = (char *) CPLCalloc(1,nFieldListLen);

/* -------------------------------------------------------------------- */
/*      Build list of old fields, and the list of new fields.           */
/* -------------------------------------------------------------------- */
    const char *pszType;
    sprintf( pszOldFieldList, "%s", "OGC_FID" );
    sprintf( pszNewFieldList, "%s", "OGC_FID INTEGER PRIMARY KEY" );
    
    int iNextOrdinal = 3; /* _rowid_ is 1, OGC_FID is 2 */

    if( poFeatureDefn->GetGeomType() != wkbNone )
    {
        strcat( pszOldFieldList, ", WKT_GEOMETRY" );
        strcat( pszNewFieldList, ", WKT_GEOMETRY VARCHAR" );
        iNextOrdinal++;
    }

    for( iField = 0; iField < poFeatureDefn->GetFieldCount(); iField++ )
    {
        OGRFieldDefn *poFldDefn = poFeatureDefn->GetFieldDefn(iField);

        // we already added OGC_FID so don't do it again
        if( EQUAL(poFldDefn->GetNameRef(),"OGC_FID") )
            continue;

        if( poFldDefn->GetType() == OFTInteger )
            pszType = "INTEGER";
        else if( poFldDefn->GetType() == OFTReal )
            pszType = "FLOAT";
        else
            pszType = "VARCHAR";
        
        sprintf( pszOldFieldList+strlen(pszOldFieldList), 
                 ", '%s'", poFldDefn->GetNameRef() );

        sprintf( pszNewFieldList+strlen(pszNewFieldList), 
                 ", '%s' %s", poFldDefn->GetNameRef(), pszType );

        iNextOrdinal++;
    }

/* -------------------------------------------------------------------- */
/*      Add the new field.                                              */
/* -------------------------------------------------------------------- */
    if( oField.GetType() == OFTInteger )
        pszType = "INTEGER";
    else if( oField.GetType() == OFTReal )
        pszType = "FLOAT";
    else
        pszType = "VARCHAR";
    
    sprintf( pszNewFieldList+strlen(pszNewFieldList), 
             ", '%s' %s", oField.GetNameRef(), pszType );

/* ==================================================================== */
/*      Backup, destroy, recreate and repopulate the table.  SQLite     */
/*      has no ALTER TABLE so we have to do all this to add a           */
/*      column.                                                         */
/* ==================================================================== */

/* -------------------------------------------------------------------- */
/*      Do this all in a transaction.                                   */
/* -------------------------------------------------------------------- */
    poDS->SoftStartTransaction();

/* -------------------------------------------------------------------- */
/*      Make a backup of the table.                                     */
/* -------------------------------------------------------------------- */
    int rc;
    char *pszErrMsg = NULL;
    sqlite3 *hDB = poDS->GetDB();
    
    rc = sqlite3_exec( hDB, 
                       CPLSPrintf( "CREATE TEMPORARY TABLE t1_back(%s)",
                                   pszOldFieldList ),
                       NULL, NULL, &pszErrMsg );

    if( rc == SQLITE_OK )
        rc = sqlite3_exec( hDB, 
                           CPLSPrintf( "INSERT INTO t1_back SELECT %s FROM '%s'",
                                       pszOldFieldList, 
                                       poFeatureDefn->GetName() ),
                           NULL, NULL, &pszErrMsg );


/* -------------------------------------------------------------------- */
/*      Drop the original table, and recreate with new field.           */
/* -------------------------------------------------------------------- */
    if( rc == SQLITE_OK )
        rc = sqlite3_exec( hDB, 
                           CPLSPrintf( "DROP TABLE '%s'", 
                                       poFeatureDefn->GetName() ),
                           NULL, NULL, &pszErrMsg );

    if( rc == SQLITE_OK )
    {
        const char *pszCmd = 
            CPLSPrintf( "CREATE TABLE '%s' (%s)", 
                        poFeatureDefn->GetName(),
                        pszNewFieldList );
        rc = sqlite3_exec( hDB, pszCmd, 
                           NULL, NULL, &pszErrMsg );

        CPLDebug( "OGR_SQLITE", "exec(%s)", pszCmd );
    }

/* -------------------------------------------------------------------- */
/*      Copy backup field values into new table.                        */
/* -------------------------------------------------------------------- */
    
    if( rc == SQLITE_OK )
        rc = sqlite3_exec( hDB, 
                           CPLSPrintf( "INSERT INTO '%s' SELECT %s, NULL FROM t1_back",
                                       poFeatureDefn->GetName(),
                                       pszOldFieldList ),
                           NULL, NULL, &pszErrMsg );


/* -------------------------------------------------------------------- */
/*      Cleanup backup table.                                           */
/* -------------------------------------------------------------------- */
    
    if( rc == SQLITE_OK )
        rc = sqlite3_exec( hDB, 
                           CPLSPrintf( "DROP TABLE t1_back" ),
                           NULL, NULL, &pszErrMsg );

/* -------------------------------------------------------------------- */
/*      COMMIT on success or ROLLBACK on failuire.                      */
/* -------------------------------------------------------------------- */
    if( rc == SQLITE_OK )
    {
        poDS->SoftCommit();
    }
    else
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Failed to add field %s to table %s:\n %s",
                  oField.GetNameRef(), poFeatureDefn->GetName(), 
                  pszErrMsg );
        sqlite3_free( pszErrMsg );

        poDS->SoftRollback();

        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Add the field to the OGRFeatureDefn.                            */
/* -------------------------------------------------------------------- */
    int iNewField;

    poFeatureDefn->AddFieldDefn( &oField );

    iNewField = poFeatureDefn->GetFieldCount() - 1;
    panFieldOrdinals = (int *) 
        CPLRealloc(panFieldOrdinals, (iNewField+1) * sizeof(int) );
    panFieldOrdinals[iNewField] = iNextOrdinal;

    return OGRERR_NONE;
}

/************************************************************************/
/*                             SetFeature()                             */
/************************************************************************/

OGRErr OGRSQLiteTableLayer::SetFeature( OGRFeature *poFeature )

{
    CPLAssert( pszFIDColumn != NULL );
    
    if( poFeature->GetFID() == OGRNullFID )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "SetFeature() with unset FID fails." );
        return OGRERR_FAILURE;
    }
/* -------------------------------------------------------------------- */
/*      Drop the record with this FID.                                  */
/* -------------------------------------------------------------------- */
    int rc;
    char *pszErrMsg = NULL;
    const char *pszSQL;

    pszSQL = 
        CPLSPrintf( "DELETE FROM '%s' WHERE \"%s\" = %d", 
                    poFeatureDefn->GetName(), 
                    pszFIDColumn,
                    poFeature->GetFID() );

    CPLDebug( "OGR_SQLITE", "exec(%s)", pszSQL );
    
    rc = sqlite3_exec( poDS->GetDB(), pszSQL,
                       NULL, NULL, &pszErrMsg );
    
    if( rc != SQLITE_OK )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Attempt to delete old feature with FID %d failed.\n%s", 
                  poFeature->GetFID(), pszErrMsg );
        return OGRERR_FAILURE;
    }
    
/* -------------------------------------------------------------------- */
/*      Recreate the feature.                                           */
/* -------------------------------------------------------------------- */
    return CreateFeature( poFeature );
}

/************************************************************************/
/*                           CreateFeature()                            */
/************************************************************************/

OGRErr OGRSQLiteTableLayer::CreateFeature( OGRFeature *poFeature )

{
    std::string    oCommand;
    std::string    oValues;
    int            bNeedComma = FALSE;

    ResetReading();

/* -------------------------------------------------------------------- */
/*      Form the INSERT command.                                        */
/* -------------------------------------------------------------------- */
    oCommand += CPLSPrintf( "INSERT INTO '%s' (", poFeatureDefn->GetName() );

/* -------------------------------------------------------------------- */
/*      Add FID if we have a cleartext FID column.                      */
/* -------------------------------------------------------------------- */
    if( pszFIDColumn != NULL && !EQUAL(pszFIDColumn,"OGC_FID") 
        && poFeature->GetFID() != OGRNullFID )
    {
        oCommand += pszFIDColumn;

        oValues += CPLSPrintf( "%d", poFeature->GetFID() );
        bNeedComma = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Add geometry.                                                   */
/* -------------------------------------------------------------------- */
    if( pszGeomColumn != NULL && poFeature->GetGeometryRef() != NULL )
    {
        char *pszWKT = NULL;

        if( bNeedComma )
        {
            oCommand += ",";
            oValues += ",";
        }

        oCommand += pszGeomColumn;

        poFeature->GetGeometryRef()->exportToWkt( &pszWKT );
        oValues += "'";
        oValues += pszWKT;
        oValues += "'";
        CPLFree( pszWKT );

        bNeedComma = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Add field values.                                               */
/* -------------------------------------------------------------------- */
    int iField;

    for( iField = 0; iField < poFeatureDefn->GetFieldCount(); iField++ )
    {
        const char *pszRawValue;

        if( !poFeature->IsFieldSet( iField ) )
            continue;

        if( bNeedComma )
        {
            oCommand += ",";
            oValues += ",";
        }

        oCommand += "'";
        oCommand +=poFeatureDefn->GetFieldDefn(iField)->GetNameRef();
        oCommand += "'";

        pszRawValue = poFeature->GetFieldAsString( iField );
        if( strchr( pszRawValue, '\'' ) != NULL )
        {
            char *pszEscapedValue = 
                CPLEscapeString( pszRawValue, -1, CPLES_SQL );
            oValues += "'";
            oValues += pszEscapedValue;
            oValues += "'";

            CPLFree( pszEscapedValue );
        }
        else
        {
            oValues += "'";
            oValues += pszRawValue;
            oValues += "'";
        }
            
        bNeedComma = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Merge final command.                                            */
/* -------------------------------------------------------------------- */
    oCommand += ") VALUES (";
    oCommand += oValues;
    oCommand += ")";

/* -------------------------------------------------------------------- */
/*      Execute the insert.                                             */
/* -------------------------------------------------------------------- */
    int rc;
    char *pszErrMsg = NULL;

    CPLDebug( "OGR_SQLITE", "exec(%s)", oCommand.c_str() );

    rc = sqlite3_exec( poDS->GetDB(), oCommand.c_str(), 
                       NULL, NULL, &pszErrMsg );

    if( rc != SQLITE_OK )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "CreateFeature() failed: %s",
                  pszErrMsg );
        sqlite3_free( pszErrMsg );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      We likely ought to consider fetching the rowid/fid and          */
/*      putting it back in the feature.                                 */
/* -------------------------------------------------------------------- */
    // todo 

    return OGRERR_NONE;
}