Package org.teiid.query.rewriter

Class QueryRewriter

java.lang.Object

org.teiid.query.rewriter.QueryRewriter

public class QueryRewriter
extends Object

Rewrites commands and command fragments to a form that is better for planning and execution. There is a current limitation that command objects themselves cannot change type, since the same object is always used.

Field Summary

Fields

Modifier and Type	Field	Description
static CompareCriteria	FALSE_CRITERIA
static CompareCriteria	TRUE_CRITERIA
static CompareCriteria	UNKNOWN_CRITERIA

Method Summary

Modifier and Type	Method	Description
static Command	createDeleteProcedure(Delete delete, QueryMetadataInterface metadata, CommandContext context)
static Query	createInlineViewQuery(GroupSymbol inlineGroup, Command nested, QueryMetadataInterface metadata, List<? extends Expression> actualSymbols)
static Command	createUpdateProcedure(Update update, QueryMetadataInterface metadata, CommandContext context)
static Command	evaluateAndRewrite(Command command, Evaluator eval, CommandContext context, QueryMetadataInterface metadata)
static Criteria	evaluateAndRewrite(Criteria criteria, Evaluator eval, CommandContext context, QueryMetadataInterface metadata)
static boolean	isDistinctWithGroupBy(Query query)
static boolean	isNull(Expression expr)
static void	makeSelectUnique(Select select, boolean expressionSymbolsOnly)
static Criteria	optimizeCriteria(CompoundCriteria criteria, QueryMetadataInterface metadata)	Performs simple expression flattening
static Command	rewrite(Command command, QueryMetadataInterface metadata, CommandContext context)
static Command	rewrite(Command command, QueryMetadataInterface metadata, CommandContext context, Map<ElementSymbol,Expression> variableValues)
static Command	rewriteAsUpsertProcedure(Insert insert, QueryMetadataInterface metadata, CommandContext context)
static Criteria	rewriteCriteria(Criteria criteria, CommandContext context, QueryMetadataInterface metadata)	Rewrite the criteria by evaluating some trivial cases.
static Expression	rewriteExpression(Expression expression, CommandContext context, QueryMetadataInterface metadata)
static Expression	rewriteExpression(Expression expression, CommandContext context, QueryMetadataInterface metadata, boolean rewriteSubcommands)
QueryCommand	rewriteOrderBy(QueryCommand queryCommand)	Rewrite the order by clause.
static void	rewriteOrderBy(QueryCommand queryCommand, OrderBy orderBy, List projectedSymbols, CommandContext context, QueryMetadataInterface metadata)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TRUE_CRITERIA

public static final CompareCriteria TRUE_CRITERIA

FALSE_CRITERIA

public static final CompareCriteria FALSE_CRITERIA

UNKNOWN_CRITERIA

public static final CompareCriteria UNKNOWN_CRITERIA

Method Detail

evaluateAndRewrite

public static Command evaluateAndRewrite(Command command,
                                         Evaluator eval,
                                         CommandContext context,
                                         QueryMetadataInterface metadata)
                                  throws TeiidProcessingException,
                                         TeiidComponentException

Throws:

TeiidProcessingException

TeiidComponentException

evaluateAndRewrite

public static Criteria evaluateAndRewrite(Criteria criteria,
                                          Evaluator eval,
                                          CommandContext context,
                                          QueryMetadataInterface metadata)
                                   throws TeiidProcessingException,
                                          TeiidComponentException

Throws:

TeiidProcessingException

TeiidComponentException

rewrite

public static Command rewrite(Command command,
                              QueryMetadataInterface metadata,
                              CommandContext context,
                              Map<ElementSymbol,Expression> variableValues)
                       throws TeiidComponentException,
                              TeiidProcessingException

Throws:

TeiidComponentException

TeiidProcessingException

rewrite

public static Command rewrite(Command command,
                              QueryMetadataInterface metadata,
                              CommandContext context)
                       throws TeiidComponentException,
                              TeiidProcessingException

Throws:

TeiidComponentException

TeiidProcessingException

isDistinctWithGroupBy

public static boolean isDistinctWithGroupBy(Query query)

rewriteOrderBy

public QueryCommand rewriteOrderBy(QueryCommand queryCommand)
                            throws TeiidComponentException,
                                   TeiidProcessingException

Rewrite the order by clause. Unrelated order by expressions will cause the creation of nested inline views.

Parameters:

queryCommand -

Throws:

TeiidComponentException

TeiidProcessingException

rewriteOrderBy

public static void rewriteOrderBy(QueryCommand queryCommand,
                                  OrderBy orderBy,
                                  List projectedSymbols,
                                  CommandContext context,
                                  QueryMetadataInterface metadata)
                           throws TeiidComponentException,
                                  TeiidProcessingException

Throws:

TeiidComponentException

TeiidProcessingException

rewriteCriteria

public static Criteria rewriteCriteria(Criteria criteria,
                                       CommandContext context,
                                       QueryMetadataInterface metadata)
                                throws TeiidComponentException,
                                       TeiidProcessingException

Rewrite the criteria by evaluating some trivial cases.

Parameters:

criteria - The criteria to rewrite

metadata -

Returns:

The re-written criteria

Throws:

TeiidComponentException

TeiidProcessingException

optimizeCriteria

public static Criteria optimizeCriteria(CompoundCriteria criteria,
                                        QueryMetadataInterface metadata)

Performs simple expression flattening

Parameters:

criteria -

Returns:

isNull

public static boolean isNull(Expression expr)

rewriteExpression

public static Expression rewriteExpression(Expression expression,
                                           CommandContext context,
                                           QueryMetadataInterface metadata)
                                    throws TeiidComponentException,
                                           TeiidProcessingException

Throws:

TeiidComponentException

TeiidProcessingException

rewriteExpression

public static Expression rewriteExpression(Expression expression,
                                           CommandContext context,
                                           QueryMetadataInterface metadata,
                                           boolean rewriteSubcommands)
                                    throws TeiidComponentException,
                                           TeiidProcessingException

Throws:

TeiidComponentException

TeiidProcessingException

rewriteAsUpsertProcedure

public static Command rewriteAsUpsertProcedure(Insert insert,
                                               QueryMetadataInterface metadata,
                                               CommandContext context)
                                        throws TeiidComponentException,
                                               QueryMetadataException,
                                               QueryValidatorException,
                                               QueryResolverException,
                                               TeiidProcessingException

Throws:

TeiidComponentException

QueryMetadataException

QueryValidatorException

QueryResolverException

TeiidProcessingException

createInlineViewQuery

public static Query createInlineViewQuery(GroupSymbol inlineGroup,
                                          Command nested,
                                          QueryMetadataInterface metadata,
                                          List<? extends Expression> actualSymbols)
                                   throws QueryMetadataException,
                                          QueryResolverException,
                                          TeiidComponentException

Throws:

QueryMetadataException

QueryResolverException

TeiidComponentException

makeSelectUnique

public static void makeSelectUnique(Select select,
                                    boolean expressionSymbolsOnly)

createDeleteProcedure

public static Command createDeleteProcedure(Delete delete,
                                            QueryMetadataInterface metadata,
                                            CommandContext context)
                                     throws QueryResolverException,
                                            QueryMetadataException,
                                            TeiidComponentException,
                                            TeiidProcessingException

Throws:

QueryResolverException

QueryMetadataException

TeiidComponentException

TeiidProcessingException

createUpdateProcedure

public static Command createUpdateProcedure(Update update,
                                            QueryMetadataInterface metadata,
                                            CommandContext context)
                                     throws QueryResolverException,
                                            QueryMetadataException,
                                            TeiidComponentException,
                                            TeiidProcessingException

Throws:

QueryResolverException

QueryMetadataException

TeiidComponentException

TeiidProcessingException