Examples with StatementClassMapping org.datanucleus.store.rdbms.query.StatementClassMapping used on opensource projects

Example 16 with StatementClassMapping

use of org.datanucleus.store.rdbms.query.StatementClassMapping in project datanucleus-rdbms by datanucleus.

the class FKSetStore method iterator.

/**
 * Accessor for an iterator for the set.
 * @param ownerOP ObjectProvider for the owner.
 * @return Iterator for the set.
 */
public Iterator<E> iterator(ObjectProvider ownerOP) {
    ExecutionContext ec = ownerOP.getExecutionContext();
    if (elementInfo == null || elementInfo.length == 0) {
        return null;
    }
    // Generate the statement, and statement mapping/parameter information
    IteratorStatement iterStmt = getIteratorStatement(ec, ec.getFetchPlan(), true);
    SelectStatement sqlStmt = iterStmt.getSelectStatement();
    StatementClassMapping iteratorMappingClass = iterStmt.getStatementClassMapping();
    // Input parameter(s) - the owner
    int inputParamNum = 1;
    StatementMappingIndex ownerStmtMapIdx = new StatementMappingIndex(ownerMapping);
    if (sqlStmt.getNumberOfUnions() > 0) {
        // Add parameter occurrence for each union of statement
        for (int j = 0; j < sqlStmt.getNumberOfUnions() + 1; j++) {
            int[] paramPositions = new int[ownerMapping.getNumberOfDatastoreMappings()];
            for (int k = 0; k < ownerMapping.getNumberOfDatastoreMappings(); k++) {
                paramPositions[k] = inputParamNum++;
            }
            ownerStmtMapIdx.addParameterOccurrence(paramPositions);
        }
    } else {
        int[] paramPositions = new int[ownerMapping.getNumberOfDatastoreMappings()];
        for (int k = 0; k < ownerMapping.getNumberOfDatastoreMappings(); k++) {
            paramPositions[k] = inputParamNum++;
        }
        ownerStmtMapIdx.addParameterOccurrence(paramPositions);
    }
    if (ec.getTransaction().getSerializeRead() != null && ec.getTransaction().getSerializeRead()) {
        sqlStmt.addExtension(SQLStatement.EXTENSION_LOCK_FOR_UPDATE, true);
    }
    String stmt = sqlStmt.getSQLText().toSQL();
    try {
        ManagedConnection mconn = storeMgr.getConnectionManager().getConnection(ec);
        SQLController sqlControl = storeMgr.getSQLController();
        try {
            // Create the statement
            PreparedStatement ps = sqlControl.getStatementForQuery(mconn, stmt);
            // Set the owner
            ObjectProvider stmtOwnerOP = BackingStoreHelper.getOwnerObjectProviderForBackingStore(ownerOP);
            int numParams = ownerStmtMapIdx.getNumberOfParameterOccurrences();
            for (int paramInstance = 0; paramInstance < numParams; paramInstance++) {
                ownerStmtMapIdx.getMapping().setObject(ec, ps, ownerStmtMapIdx.getParameterPositionsForOccurrence(paramInstance), stmtOwnerOP.getObject());
            }
            try {
                ResultSet rs = sqlControl.executeStatementQuery(ec, mconn, stmt, ps);
                try {
                    ResultObjectFactory rof = null;
                    if (elementsAreEmbedded || elementsAreSerialised) {
                        throw new NucleusException("Cannot have FK set with non-persistent objects");
                    }
                    rof = new PersistentClassROF(ec, rs, false, iteratorMappingClass, elementCmd, clr.classForName(elementType));
                    return new CollectionStoreIterator(ownerOP, rs, rof, this);
                } finally {
                    rs.close();
                }
            } finally {
                sqlControl.closeStatement(mconn, ps);
            }
        } finally {
            mconn.release();
        }
    } catch (SQLException | MappedDatastoreException e) {
        throw new NucleusDataStoreException(Localiser.msg("056006", stmt), e);
    }
}

Example 17 with StatementClassMapping

use of org.datanucleus.store.rdbms.query.StatementClassMapping in project datanucleus-rdbms by datanucleus.

the class JoinArrayStore method iterator.

/**
 * Method to return an iterator to the array.
 * @param ownerOP ObjectProvider for the owner of the array
 */
public Iterator<E> iterator(ObjectProvider ownerOP) {
    ExecutionContext ec = ownerOP.getExecutionContext();
    // Generate the statement, and statement mapping/parameter information
    IteratorStatement iterStmt = getIteratorStatement(ec, ec.getFetchPlan(), true);
    SelectStatement sqlStmt = iterStmt.sqlStmt;
    StatementClassMapping iteratorMappingClass = iterStmt.stmtClassMapping;
    // Input parameter(s) - the owner
    int inputParamNum = 1;
    StatementMappingIndex ownerIdx = new StatementMappingIndex(ownerMapping);
    if (sqlStmt.getNumberOfUnions() > 0) {
        // Add parameter occurrence for each union of statement
        for (int j = 0; j < sqlStmt.getNumberOfUnions() + 1; j++) {
            int[] paramPositions = new int[ownerMapping.getNumberOfDatastoreMappings()];
            for (int k = 0; k < paramPositions.length; k++) {
                paramPositions[k] = inputParamNum++;
            }
            ownerIdx.addParameterOccurrence(paramPositions);
        }
    } else {
        int[] paramPositions = new int[ownerMapping.getNumberOfDatastoreMappings()];
        for (int k = 0; k < paramPositions.length; k++) {
            paramPositions[k] = inputParamNum++;
        }
        ownerIdx.addParameterOccurrence(paramPositions);
    }
    StatementParameterMapping iteratorMappingParams = new StatementParameterMapping();
    iteratorMappingParams.addMappingForParameter("owner", ownerIdx);
    if (ec.getTransaction().getSerializeRead() != null && ec.getTransaction().getSerializeRead()) {
        sqlStmt.addExtension(SQLStatement.EXTENSION_LOCK_FOR_UPDATE, true);
    }
    String stmt = sqlStmt.getSQLText().toSQL();
    try {
        ManagedConnection mconn = storeMgr.getConnectionManager().getConnection(ec);
        SQLController sqlControl = storeMgr.getSQLController();
        try {
            // Create the statement
            PreparedStatement ps = sqlControl.getStatementForQuery(mconn, stmt);
            // Set the owner
            ObjectProvider stmtOwnerOP = BackingStoreHelper.getOwnerObjectProviderForBackingStore(ownerOP);
            int numParams = ownerIdx.getNumberOfParameterOccurrences();
            for (int paramInstance = 0; paramInstance < numParams; paramInstance++) {
                ownerIdx.getMapping().setObject(ec, ps, ownerIdx.getParameterPositionsForOccurrence(paramInstance), stmtOwnerOP.getObject());
            }
            try {
                ResultSet rs = sqlControl.executeStatementQuery(ec, mconn, stmt, ps);
                try {
                    if (elementsAreEmbedded || elementsAreSerialised) {
                        // No ResultObjectFactory needed - handled by SetStoreIterator
                        return new ArrayStoreIterator(ownerOP, rs, null, this);
                    } else if (elementMapping instanceof ReferenceMapping) {
                        // No ResultObjectFactory needed - handled by SetStoreIterator
                        return new ArrayStoreIterator(ownerOP, rs, null, this);
                    } else {
                        ResultObjectFactory rof = new PersistentClassROF(ec, rs, false, iteratorMappingClass, elementCmd, clr.classForName(elementType));
                        return new ArrayStoreIterator(ownerOP, rs, rof, this);
                    }
                } finally {
                    rs.close();
                }
            } finally {
                sqlControl.closeStatement(mconn, ps);
            }
        } finally {
            mconn.release();
        }
    } catch (SQLException | MappedDatastoreException e) {
        throw new NucleusDataStoreException(Localiser.msg("056006", stmt), e);
    }
}

Example 18 with StatementClassMapping

use of org.datanucleus.store.rdbms.query.StatementClassMapping in project datanucleus-rdbms by datanucleus.

the class JoinArrayStore method getIteratorStatement.

/**
 * Method to return the SQLStatement and mapping for an iterator for this backing store.
 * Create a statement of the form
 * <pre>
 * SELECT ELEM_COLS
 * FROM JOIN_TBL
 *   [JOIN ELEM_TBL ON ELEM_TBL.ID = JOIN_TBL.ELEM_ID]
 * [WHERE]
 *   [JOIN_TBL.OWNER_ID = {value}] [AND]
 *   [JOIN_TBL.DISCRIM = {discrimValue}]
 * [ORDER BY {orderClause}]
 * </pre>
 * @param ec ExecutionContext
 * @param fp FetchPlan to use in determing which fields of element to select
 * @param addRestrictionOnOwner Whether to restrict to a particular owner (otherwise functions as bulk fetch for many owners).
 * @return The SQLStatement and its associated StatementClassMapping
 */
public IteratorStatement getIteratorStatement(ExecutionContext ec, FetchPlan fp, boolean addRestrictionOnOwner) {
    SelectStatement sqlStmt = null;
    SQLExpressionFactory exprFactory = storeMgr.getSQLExpressionFactory();
    StatementClassMapping iteratorMappingClass = null;
    if (elementsAreEmbedded || elementsAreSerialised) {
        // Element = embedded, serialised (maybe Non-PC)
        // Just select the join table since we're going to return the embedded/serialised columns from it
        sqlStmt = new SelectStatement(storeMgr, containerTable, null, null);
        sqlStmt.setClassLoaderResolver(clr);
        // Select the element column - first select is assumed by SetStoreIterator
        sqlStmt.select(sqlStmt.getPrimaryTable(), elementMapping, null);
    // TODO If embedded element and it includes 1-1/N-1 in FetchPlan then select its fields also
    } else if (elementMapping instanceof ReferenceMapping) {
        // Element = Reference type (interface/Object)
        // Just select the join table since we're going to return the implementation id columns only
        sqlStmt = new SelectStatement(storeMgr, containerTable, null, null);
        sqlStmt.setClassLoaderResolver(clr);
        // Select the reference column(s) - first select is assumed by SetStoreIterator
        sqlStmt.select(sqlStmt.getPrimaryTable(), elementMapping, null);
    } else {
        // Element = PC
        // Join to the element table(s)
        iteratorMappingClass = new StatementClassMapping();
        for (int i = 0; i < elementInfo.length; i++) {
            // TODO This will only work if all element types have a discriminator
            final int elementNo = i;
            final Class elementCls = clr.classForName(elementInfo[elementNo].getClassName());
            SelectStatement elementStmt = null;
            if (elementInfo[elementNo].getDiscriminatorStrategy() != null && elementInfo[elementNo].getDiscriminatorStrategy() != DiscriminatorStrategy.NONE) {
                // The element uses a discriminator so just use that in the SELECT
                String elementType = ownerMemberMetaData.getCollection().getElementType();
                if (ClassUtils.isReferenceType(clr.classForName(elementType))) {
                    String[] clsNames = storeMgr.getNucleusContext().getMetaDataManager().getClassesImplementingInterface(elementType, clr);
                    Class[] cls = new Class[clsNames.length];
                    for (int j = 0; j < clsNames.length; j++) {
                        cls[j] = clr.classForName(clsNames[j]);
                    }
                    SelectStatementGenerator stmtGen = new DiscriminatorStatementGenerator(storeMgr, clr, cls, true, null, null, containerTable, null, elementMapping);
                    if (allowNulls) {
                        stmtGen.setOption(SelectStatementGenerator.OPTION_ALLOW_NULLS);
                    }
                    elementStmt = stmtGen.getStatement(ec);
                } else {
                    SelectStatementGenerator stmtGen = new DiscriminatorStatementGenerator(storeMgr, clr, elementCls, true, null, null, containerTable, null, elementMapping);
                    if (allowNulls) {
                        stmtGen.setOption(SelectStatementGenerator.OPTION_ALLOW_NULLS);
                    }
                    elementStmt = stmtGen.getStatement(ec);
                }
                iterateUsingDiscriminator = true;
            } else {
                // No discriminator, but subclasses so use UNIONs
                SelectStatementGenerator stmtGen = new UnionStatementGenerator(storeMgr, clr, elementCls, true, null, null, containerTable, null, elementMapping);
                stmtGen.setOption(SelectStatementGenerator.OPTION_SELECT_DN_TYPE);
                if (allowNulls) {
                    stmtGen.setOption(SelectStatementGenerator.OPTION_ALLOW_NULLS);
                }
                iteratorMappingClass.setNucleusTypeColumnName(UnionStatementGenerator.DN_TYPE_COLUMN);
                elementStmt = stmtGen.getStatement(ec);
            }
            if (sqlStmt == null) {
                sqlStmt = elementStmt;
            } else {
                sqlStmt.union(elementStmt);
            }
        }
        if (sqlStmt == null) {
            throw new NucleusException("Error in generation of SQL statement for iterator over (Join) array. Statement is null");
        }
        // Select the required fields
        SQLTable elementSqlTbl = sqlStmt.getTable(elementInfo[0].getDatastoreClass(), sqlStmt.getPrimaryTable().getGroupName());
        SQLStatementHelper.selectFetchPlanOfSourceClassInStatement(sqlStmt, iteratorMappingClass, fp, elementSqlTbl, elementCmd, fp.getMaxFetchDepth());
    }
    if (addRestrictionOnOwner) {
        // Apply condition on join-table owner field to filter by owner
        SQLTable ownerSqlTbl = SQLStatementHelper.getSQLTableForMappingOfTable(sqlStmt, sqlStmt.getPrimaryTable(), ownerMapping);
        SQLExpression ownerExpr = exprFactory.newExpression(sqlStmt, ownerSqlTbl, ownerMapping);
        SQLExpression ownerVal = exprFactory.newLiteralParameter(sqlStmt, ownerMapping, null, "OWNER");
        sqlStmt.whereAnd(ownerExpr.eq(ownerVal), true);
    }
    if (relationDiscriminatorMapping != null) {
        // Apply condition on distinguisher field to filter by distinguisher (when present)
        SQLTable distSqlTbl = SQLStatementHelper.getSQLTableForMappingOfTable(sqlStmt, sqlStmt.getPrimaryTable(), relationDiscriminatorMapping);
        SQLExpression distExpr = exprFactory.newExpression(sqlStmt, distSqlTbl, relationDiscriminatorMapping);
        SQLExpression distVal = exprFactory.newLiteral(sqlStmt, relationDiscriminatorMapping, relationDiscriminatorValue);
        sqlStmt.whereAnd(distExpr.eq(distVal), true);
    }
    if (orderMapping != null) {
        // Order by the ordering column, when present
        SQLTable orderSqlTbl = SQLStatementHelper.getSQLTableForMappingOfTable(sqlStmt, sqlStmt.getPrimaryTable(), orderMapping);
        SQLExpression[] orderExprs = new SQLExpression[orderMapping.getNumberOfDatastoreMappings()];
        boolean[] descendingOrder = new boolean[orderMapping.getNumberOfDatastoreMappings()];
        orderExprs[0] = exprFactory.newExpression(sqlStmt, orderSqlTbl, orderMapping);
        sqlStmt.setOrdering(orderExprs, descendingOrder);
    }
    return new IteratorStatement(this, sqlStmt, iteratorMappingClass);
}

Example 19 with StatementClassMapping

use of org.datanucleus.store.rdbms.query.StatementClassMapping in project datanucleus-rdbms by datanucleus.

the class JoinSetStore method iterator.

/**
 * Accessor for an iterator for the set.
 * @param ownerOP ObjectProvider for the set.
 * @return Iterator for the set.
 */
public Iterator<E> iterator(ObjectProvider ownerOP) {
    ExecutionContext ec = ownerOP.getExecutionContext();
    // Generate the statement, and statement mapping/parameter information
    IteratorStatement iterStmt = getIteratorStatement(ec, ec.getFetchPlan(), true);
    SelectStatement sqlStmt = iterStmt.sqlStmt;
    StatementClassMapping iteratorMappingClass = iterStmt.stmtClassMapping;
    // Input parameter(s) - the owner
    int inputParamNum = 1;
    StatementMappingIndex ownerStmtMapIdx = new StatementMappingIndex(ownerMapping);
    if (sqlStmt.getNumberOfUnions() > 0) {
        // Add parameter occurrence for each union of statement
        for (int j = 0; j < sqlStmt.getNumberOfUnions() + 1; j++) {
            int[] paramPositions = new int[ownerMapping.getNumberOfDatastoreMappings()];
            for (int k = 0; k < paramPositions.length; k++) {
                paramPositions[k] = inputParamNum++;
            }
            ownerStmtMapIdx.addParameterOccurrence(paramPositions);
        }
    } else {
        int[] paramPositions = new int[ownerMapping.getNumberOfDatastoreMappings()];
        for (int k = 0; k < paramPositions.length; k++) {
            paramPositions[k] = inputParamNum++;
        }
        ownerStmtMapIdx.addParameterOccurrence(paramPositions);
    }
    if (ec.getTransaction().getSerializeRead() != null && ec.getTransaction().getSerializeRead()) {
        sqlStmt.addExtension(SQLStatement.EXTENSION_LOCK_FOR_UPDATE, true);
    }
    String stmt = sqlStmt.getSQLText().toSQL();
    try {
        ManagedConnection mconn = storeMgr.getConnectionManager().getConnection(ec);
        SQLController sqlControl = storeMgr.getSQLController();
        try {
            // Create the statement
            PreparedStatement ps = sqlControl.getStatementForQuery(mconn, stmt);
            // Set the owner
            ObjectProvider stmtOwnerOP = BackingStoreHelper.getOwnerObjectProviderForBackingStore(ownerOP);
            int numParams = ownerStmtMapIdx.getNumberOfParameterOccurrences();
            for (int paramInstance = 0; paramInstance < numParams; paramInstance++) {
                ownerStmtMapIdx.getMapping().setObject(ec, ps, ownerStmtMapIdx.getParameterPositionsForOccurrence(paramInstance), stmtOwnerOP.getObject());
            }
            try {
                ResultSet rs = sqlControl.executeStatementQuery(ec, mconn, stmt, ps);
                try {
                    if (elementsAreEmbedded || elementsAreSerialised) {
                        // No ResultObjectFactory needed - handled by SetStoreIterator
                        return new CollectionStoreIterator(ownerOP, rs, null, this);
                    } else if (elementMapping instanceof ReferenceMapping) {
                        // No ResultObjectFactory needed - handled by SetStoreIterator
                        return new CollectionStoreIterator(ownerOP, rs, null, this);
                    } else {
                        ResultObjectFactory rof = new PersistentClassROF(ec, rs, false, iteratorMappingClass, elementCmd, clr.classForName(elementType));
                        return new CollectionStoreIterator(ownerOP, rs, rof, this);
                    }
                } finally {
                    rs.close();
                }
            } finally {
                sqlControl.closeStatement(mconn, ps);
            }
        } finally {
            mconn.release();
        }
    } catch (SQLException | MappedDatastoreException e) {
        throw new NucleusDataStoreException(Localiser.msg("056006", stmt), e);
    }
}

Example 20 with StatementClassMapping

use of org.datanucleus.store.rdbms.query.StatementClassMapping in project datanucleus-rdbms by datanucleus.

the class JoinSetStore method getIteratorStatement.

/**
 * Method to return the SQLStatement and mapping for an iterator for this backing store.
 * Create a statement of the form
 * <pre>
 * SELECT ELEM_COLS
 * FROM JOIN_TBL
 *   [JOIN ELEM_TBL ON ELEM_TBL.ID = JOIN_TBL.ELEM_ID]
 * [WHERE]
 *   [JOIN_TBL.OWNER_ID = {value}] [AND]
 *   [JOIN_TBL.DISCRIM = {discrimValue}]
 * [ORDER BY {orderClause}]
 * </pre>
 * @param ec ExecutionContext
 * @param fp FetchPlan to use in determining which fields of element to select
 * @param addRestrictionOnOwner Whether to restrict to a particular owner (otherwise functions as bulk fetch for many owners).
 * @return The SQLStatement and its associated StatementClassMapping
 */
public IteratorStatement getIteratorStatement(ExecutionContext ec, FetchPlan fp, boolean addRestrictionOnOwner) {
    SelectStatement sqlStmt = null;
    SQLExpressionFactory exprFactory = storeMgr.getSQLExpressionFactory();
    StatementClassMapping iteratorMappingClass = null;
    if (elementsAreEmbedded || elementsAreSerialised) {
        // Element = embedded, serialised (maybe Non-PC)
        // Just select the join table since we're going to return the embedded/serialised columns from it
        sqlStmt = new SelectStatement(storeMgr, containerTable, null, null);
        sqlStmt.setClassLoaderResolver(clr);
        // Select the element column - first select is assumed by SetStoreIterator
        sqlStmt.select(sqlStmt.getPrimaryTable(), elementMapping, null);
    // TODO If embedded element and it includes 1-1/N-1 in FetchPlan then select its fields also
    } else if (elementMapping instanceof ReferenceMapping) {
        // Element = Reference type (interface/Object)
        // Just select the join table since we're going to return the implementation id columns only
        sqlStmt = new SelectStatement(storeMgr, containerTable, null, null);
        sqlStmt.setClassLoaderResolver(clr);
        // Select the reference column(s) - first select is assumed by SetStoreIterator
        sqlStmt.select(sqlStmt.getPrimaryTable(), elementMapping, null);
    } else {
        // Element = PC
        // Join to the element table(s)
        iteratorMappingClass = new StatementClassMapping();
        for (int i = 0; i < elementInfo.length; i++) {
            final int elementNo = i;
            final Class elementCls = clr.classForName(elementInfo[elementNo].getClassName());
            SelectStatement elementStmt = null;
            if (elementInfo[elementNo].getDiscriminatorStrategy() != null && elementInfo[elementNo].getDiscriminatorStrategy() != DiscriminatorStrategy.NONE) {
                // The element uses a discriminator so just use that in the SELECT
                String elementType = ownerMemberMetaData.getCollection().getElementType();
                if (ClassUtils.isReferenceType(clr.classForName(elementType))) {
                    String[] clsNames = storeMgr.getNucleusContext().getMetaDataManager().getClassesImplementingInterface(elementType, clr);
                    Class[] cls = new Class[clsNames.length];
                    for (int j = 0; j < clsNames.length; j++) {
                        cls[j] = clr.classForName(clsNames[j]);
                    }
                    SelectStatementGenerator stmtGen = new DiscriminatorStatementGenerator(storeMgr, clr, cls, true, null, null, containerTable, null, elementMapping);
                    if (allowNulls) {
                        stmtGen.setOption(SelectStatementGenerator.OPTION_ALLOW_NULLS);
                    }
                    elementStmt = stmtGen.getStatement(ec);
                } else {
                    SelectStatementGenerator stmtGen = new DiscriminatorStatementGenerator(storeMgr, clr, elementCls, true, null, null, containerTable, null, elementMapping);
                    if (allowNulls) {
                        stmtGen.setOption(SelectStatementGenerator.OPTION_ALLOW_NULLS);
                    }
                    elementStmt = stmtGen.getStatement(ec);
                }
                iterateUsingDiscriminator = true;
            } else {
                // No discriminator, but subclasses so use UNIONs
                SelectStatementGenerator stmtGen = new UnionStatementGenerator(storeMgr, clr, elementCls, true, null, null, containerTable, null, elementMapping);
                stmtGen.setOption(SelectStatementGenerator.OPTION_SELECT_DN_TYPE);
                iteratorMappingClass.setNucleusTypeColumnName(UnionStatementGenerator.DN_TYPE_COLUMN);
                elementStmt = stmtGen.getStatement(ec);
            }
            // TODO What if the first elementInfo has fields selected in one order and then the second in a different order?
            if (sqlStmt == null) {
                sqlStmt = elementStmt;
                // Select the required fields
                SQLTable elementSqlTbl = sqlStmt.getTable(elementInfo[i].getDatastoreClass(), sqlStmt.getPrimaryTable().getGroupName());
                SQLStatementHelper.selectFetchPlanOfSourceClassInStatement(sqlStmt, iteratorMappingClass, fp, elementSqlTbl, elementCmd, fp.getMaxFetchDepth());
            } else {
                // Select the required fields
                SQLTable elementSqlTbl = elementStmt.getTable(elementInfo[i].getDatastoreClass(), elementStmt.getPrimaryTable().getGroupName());
                SQLStatementHelper.selectFetchPlanOfSourceClassInStatement(elementStmt, iteratorMappingClass, fp, elementSqlTbl, elementCmd, fp.getMaxFetchDepth());
                sqlStmt.union(elementStmt);
            }
        }
    }
    if (sqlStmt == null) {
        throw new NucleusException("Error in generation of SQL statement for iterator over (Join) set. Statement is null");
    }
    if (addRestrictionOnOwner) {
        // Apply condition on join-table owner field to filter by owner
        SQLTable ownerSqlTbl = SQLStatementHelper.getSQLTableForMappingOfTable(sqlStmt, sqlStmt.getPrimaryTable(), ownerMapping);
        SQLExpression ownerExpr = exprFactory.newExpression(sqlStmt, ownerSqlTbl, ownerMapping);
        SQLExpression ownerVal = exprFactory.newLiteralParameter(sqlStmt, ownerMapping, null, "OWNER");
        sqlStmt.whereAnd(ownerExpr.eq(ownerVal), true);
    }
    if (relationDiscriminatorMapping != null) {
        // Apply condition on distinguisher field to filter by distinguisher (when present)
        SQLTable distSqlTbl = SQLStatementHelper.getSQLTableForMappingOfTable(sqlStmt, sqlStmt.getPrimaryTable(), relationDiscriminatorMapping);
        SQLExpression distExpr = exprFactory.newExpression(sqlStmt, distSqlTbl, relationDiscriminatorMapping);
        SQLExpression distVal = exprFactory.newLiteral(sqlStmt, relationDiscriminatorMapping, relationDiscriminatorValue);
        sqlStmt.whereAnd(distExpr.eq(distVal), true);
    }
    if (orderMapping != null) {
        // TODO If we have multiple roots then cannot allow this
        // Order by the ordering column, when present
        SQLTable orderSqlTbl = SQLStatementHelper.getSQLTableForMappingOfTable(sqlStmt, sqlStmt.getPrimaryTable(), orderMapping);
        SQLExpression[] orderExprs = new SQLExpression[orderMapping.getNumberOfDatastoreMappings()];
        boolean[] descendingOrder = new boolean[orderMapping.getNumberOfDatastoreMappings()];
        orderExprs[0] = exprFactory.newExpression(sqlStmt, orderSqlTbl, orderMapping);
        sqlStmt.setOrdering(orderExprs, descendingOrder);
    }
    return new IteratorStatement(this, sqlStmt, iteratorMappingClass);
}