// effects: Checks for key constraint implication problems from
// leftViewConstraints to rightViewConstraints. Adds errors/warning to m_errorLog
private void CheckImplicationKeyConstraints(ViewSchemaConstraints leftViewConstraints,
ViewSchemaConstraints rightViewConstraints)
{
// if cImpliesS is true, every rightKeyConstraint must be implied
// if it is false, at least one key constraint for each C-level
// extent must be implied
foreach (ViewKeyConstraint rightKeyConstraint in rightViewConstraints.KeyConstraints)
{
// Go through all the left Side constraints and check for implication
bool found = false;
foreach (ViewKeyConstraint leftKeyConstraint in leftViewConstraints.KeyConstraints)
{
if (leftKeyConstraint.Implies(rightKeyConstraint))
{
found = true;
break; // The implication holds - so no problem
}
}
if (false == found)
{
// No C-side key constraint implies this S-level key constraint
// Report a problem
m_errorLog.AddEntry(ViewKeyConstraint.GetErrorRecord(rightKeyConstraint));
}
}
}
// effects: Performs the validation of the cells in this and returns
// an error log of all the errors/warnings that were discovered
internal ErrorLog Validate()
{
// Check for errors not checked by "C-implies-S principle"
if (m_config.IsValidationEnabled)
{
if (PerformSingleCellChecks() == false)
{
return(m_errorLog);
}
}
else //Note that Metadata loading guarantees that DISTINCT flag is not present
{ // when update views (and validation) is disabled
if (CheckCellsWithDistinctFlag() == false)
{
return(m_errorLog);
}
}
BasicSchemaConstraints cConstraints = new BasicSchemaConstraints();
BasicSchemaConstraints sConstraints = new BasicSchemaConstraints();
// Construct intermediate "view relations" and the basic cell
// relations along with the basic constraints
ConstructCellRelationsWithConstraints(cConstraints, sConstraints);
if (m_config.IsVerboseTracing)
{
// Trace Basic constraints
Trace.WriteLine(String.Empty);
Trace.WriteLine("C-Level Basic Constraints");
Trace.WriteLine(cConstraints);
Trace.WriteLine("S-Level Basic Constraints");
Trace.WriteLine(sConstraints);
}
// Propagate the constraints
m_cViewConstraints = PropagateConstraints(cConstraints);
m_sViewConstraints = PropagateConstraints(sConstraints);
// Make some basic checks on the view and basic cell constraints
CheckConstraintSanity(cConstraints, sConstraints, m_cViewConstraints, m_sViewConstraints);
if (m_config.IsVerboseTracing)
{
// Trace View constraints
Trace.WriteLine(String.Empty);
Trace.WriteLine("C-Level View Constraints");
Trace.WriteLine(m_cViewConstraints);
Trace.WriteLine("S-Level View Constraints");
Trace.WriteLine(m_sViewConstraints);
}
// Check for implication
if (m_config.IsValidationEnabled)
{
CheckImplication(m_cViewConstraints, m_sViewConstraints);
}
return(m_errorLog);
}
private static void CheckConstraintSanity(BasicSchemaConstraints cConstraints, BasicSchemaConstraints sConstraints,
ViewSchemaConstraints cViewConstraints, ViewSchemaConstraints sViewConstraints)
{
Debug.Assert(cConstraints.KeyConstraints.Count() == cViewConstraints.KeyConstraints.Count(),
"Mismatch in number of C basic and view key constraints");
Debug.Assert(sConstraints.KeyConstraints.Count() == sViewConstraints.KeyConstraints.Count(),
"Mismatch in number of S basic and view key constraints");
}
// effects: Propagates baseConstraints derived from the cellrelations
// to the corresponding viewCellRelations and returns the list of
// propagated constraints
private static ViewSchemaConstraints PropagateConstraints(BasicSchemaConstraints baseConstraints)
{
ViewSchemaConstraints propagatedConstraints = new ViewSchemaConstraints();
// Key constraint propagation
foreach (BasicKeyConstraint keyConstraint in baseConstraints.KeyConstraints)
{
ViewKeyConstraint viewConstraint = keyConstraint.Propagate();
if (viewConstraint != null)
{
propagatedConstraints.Add(viewConstraint);
}
}
return(propagatedConstraints);
}
// effects: Checks if all sViewConstraints are implied by the
// constraints in cViewConstraints. If some S-level constraints are
// not implied, adds errors/warnings to m_errorLog
private void CheckImplication(ViewSchemaConstraints cViewConstraints, ViewSchemaConstraints sViewConstraints)
{
// Check key constraints
// i.e., if S has a key <k1, k2>, C must have a key that is a subset of this
CheckImplicationKeyConstraints(cViewConstraints, sViewConstraints);
// For updates, we need to ensure the following: for every
// extent E, table T pair, some key of E is implied by T's key
// Get all key constraints for each extent and each table
KeyToListMap <ExtentPair, ViewKeyConstraint> extentPairConstraints =
new KeyToListMap <ExtentPair, ViewKeyConstraint>(EqualityComparer <ExtentPair> .Default);
foreach (ViewKeyConstraint cKeyConstraint in cViewConstraints.KeyConstraints)
{
ExtentPair pair = new ExtentPair(cKeyConstraint.Cell.CQuery.Extent, cKeyConstraint.Cell.SQuery.Extent);
extentPairConstraints.Add(pair, cKeyConstraint);
}
// Now check that we guarantee at least one constraint per
// extent/table pair
foreach (ExtentPair extentPair in extentPairConstraints.Keys)
{
ReadOnlyCollection <ViewKeyConstraint> cKeyConstraints = extentPairConstraints.ListForKey(extentPair);
bool sImpliesSomeC = false;
// Go through all key constraints for the extent/table pair, and find one that S implies
foreach (ViewKeyConstraint cKeyConstraint in cKeyConstraints)
{
foreach (ViewKeyConstraint sKeyConstraint in sViewConstraints.KeyConstraints)
{
if (sKeyConstraint.Implies(cKeyConstraint))
{
sImpliesSomeC = true;
break; // The implication holds - so no problem
}
}
}
if (sImpliesSomeC == false)
{
// Indicate that at least one key must be ensured on the S-side
m_errorLog.AddEntry(ViewKeyConstraint.GetErrorRecord(cKeyConstraints));
}
}
}
// effects: Performs the validation of the cells in this and returns
// an error log of all the errors/warnings that were discovered
internal ErrorLog Validate()
{
// Check for errors not checked by "C-implies-S principle"
if (m_config.IsValidationEnabled)
{
if (PerformSingleCellChecks() == false)
{
return m_errorLog;
}
}
else //Note that Metadata loading guarantees that DISTINCT flag is not present
{ // when update views (and validation) is disabled
if (CheckCellsWithDistinctFlag() == false)
{
return m_errorLog;
}
}
BasicSchemaConstraints cConstraints = new BasicSchemaConstraints();
BasicSchemaConstraints sConstraints = new BasicSchemaConstraints();
// Construct intermediate "view relations" and the basic cell
// relations along with the basic constraints
ConstructCellRelationsWithConstraints(cConstraints, sConstraints);
if (m_config.IsVerboseTracing)
{
// Trace Basic constraints
Trace.WriteLine(String.Empty);
Trace.WriteLine("C-Level Basic Constraints");
Trace.WriteLine(cConstraints);
Trace.WriteLine("S-Level Basic Constraints");
Trace.WriteLine(sConstraints);
}
// Propagate the constraints
m_cViewConstraints = PropagateConstraints(cConstraints);
m_sViewConstraints = PropagateConstraints(sConstraints);
// Make some basic checks on the view and basic cell constraints
CheckConstraintSanity(cConstraints, sConstraints, m_cViewConstraints, m_sViewConstraints);
if (m_config.IsVerboseTracing)
{
// Trace View constraints
Trace.WriteLine(String.Empty);
Trace.WriteLine("C-Level View Constraints");
Trace.WriteLine(m_cViewConstraints);
Trace.WriteLine("S-Level View Constraints");
Trace.WriteLine(m_sViewConstraints);
}
// Check for implication
if (m_config.IsValidationEnabled)
{
CheckImplication(m_cViewConstraints, m_sViewConstraints);
}
return m_errorLog;
}
private static void CheckConstraintSanity(BasicSchemaConstraints cConstraints, BasicSchemaConstraints sConstraints,
ViewSchemaConstraints cViewConstraints, ViewSchemaConstraints sViewConstraints)
{
Debug.Assert(cConstraints.KeyConstraints.Count() == cViewConstraints.KeyConstraints.Count(),
"Mismatch in number of C basic and view key constraints");
Debug.Assert(sConstraints.KeyConstraints.Count() == sViewConstraints.KeyConstraints.Count(),
"Mismatch in number of S basic and view key constraints");
}
// effects: Checks for key constraint implication problems from
// leftViewConstraints to rightViewConstraints. Adds errors/warning to m_errorLog
private void CheckImplicationKeyConstraints(ViewSchemaConstraints leftViewConstraints,
ViewSchemaConstraints rightViewConstraints)
{
// if cImpliesS is true, every rightKeyConstraint must be implied
// if it is false, at least one key constraint for each C-level
// extent must be implied
foreach (ViewKeyConstraint rightKeyConstraint in rightViewConstraints.KeyConstraints)
{
// Go through all the left Side constraints and check for implication
bool found = false;
foreach (ViewKeyConstraint leftKeyConstraint in leftViewConstraints.KeyConstraints)
{
if (leftKeyConstraint.Implies(rightKeyConstraint))
{
found = true;
break; // The implication holds - so no problem
}
}
if (false == found)
{
// No C-side key constraint implies this S-level key constraint
// Report a problem
m_errorLog.AddEntry(ViewKeyConstraint.GetErrorRecord(rightKeyConstraint));
}
}
}
// effects: Checks if all sViewConstraints are implied by the
// constraints in cViewConstraints. If some S-level constraints are
// not implied, adds errors/warnings to m_errorLog
private void CheckImplication(ViewSchemaConstraints cViewConstraints, ViewSchemaConstraints sViewConstraints)
{
// Check key constraints
// i.e., if S has a key <k1, k2>, C must have a key that is a subset of this
CheckImplicationKeyConstraints(cViewConstraints, sViewConstraints);
// For updates, we need to ensure the following: for every
// extent E, table T pair, some key of E is implied by T's key
// Get all key constraints for each extent and each table
KeyToListMap<ExtentPair, ViewKeyConstraint> extentPairConstraints =
new KeyToListMap<ExtentPair, ViewKeyConstraint>(EqualityComparer<ExtentPair>.Default);
foreach (ViewKeyConstraint cKeyConstraint in cViewConstraints.KeyConstraints)
{
ExtentPair pair = new ExtentPair(cKeyConstraint.Cell.CQuery.Extent, cKeyConstraint.Cell.SQuery.Extent);
extentPairConstraints.Add(pair, cKeyConstraint);
}
// Now check that we guarantee at least one constraint per
// extent/table pair
foreach (ExtentPair extentPair in extentPairConstraints.Keys)
{
ReadOnlyCollection<ViewKeyConstraint> cKeyConstraints = extentPairConstraints.ListForKey(extentPair);
bool sImpliesSomeC = false;
// Go through all key constraints for the extent/table pair, and find one that S implies
foreach (ViewKeyConstraint cKeyConstraint in cKeyConstraints)
{
foreach (ViewKeyConstraint sKeyConstraint in sViewConstraints.KeyConstraints)
{
if (sKeyConstraint.Implies(cKeyConstraint))
{
sImpliesSomeC = true;
break; // The implication holds - so no problem
}
}
}
if (sImpliesSomeC == false)
{
// Indicate that at least one key must be ensured on the S-side
m_errorLog.AddEntry(ViewKeyConstraint.GetErrorRecord(cKeyConstraints));
}
}
}
// effects: Propagates baseConstraints derived from the cellrelations
// to the corresponding viewCellRelations and returns the list of
// propagated constraints
private static ViewSchemaConstraints PropagateConstraints(BasicSchemaConstraints baseConstraints)
{
ViewSchemaConstraints propagatedConstraints = new ViewSchemaConstraints();
// Key constraint propagation
foreach (BasicKeyConstraint keyConstraint in baseConstraints.KeyConstraints)
{
ViewKeyConstraint viewConstraint = keyConstraint.Propagate();
if (viewConstraint != null)
{
propagatedConstraints.Add(viewConstraint);
}
}
return propagatedConstraints;
}
