private static ObjectName ResolveGroupMax(TableSelectExpression expression, TableExpressionFromSet fromSet)
{
// Resolve GROUP MAX variable to a reference in this from set
ObjectName groupmaxColumn = expression.GroupMax;
if (groupmaxColumn != null)
{
ObjectName v = fromSet.ResolveReference(groupmaxColumn);
if (v == null)
{
throw new ApplicationException("Could find GROUP MAX reference '" + groupmaxColumn + "'");
}
groupmaxColumn = v;
}
return(groupmaxColumn);
}
internal static TableExpressionFromSet GenerateFromSet(TableSelectExpression selectExpression, ITableSpaceContext db)
{
// Get the 'from_clause' from the table expression
FromClause fromClause = selectExpression.From;
// Create a TableExpressionFromSet for this table expression
var fromSet = new TableExpressionFromSet(db.IsInCaseInsensitive);
// Add all tables from the 'fromClause'
foreach (FromTable fromTable in fromClause.AllTables)
{
string uniqueKey = fromTable.UniqueKey;
ObjectName alias = fromTable.Alias;
// If this is a sub-command table,
if (fromTable.IsSubQueryTable)
{
// eg. FROM ( SELECT id FROM Part )
TableSelectExpression subQuery = fromTable.SubSelect;
TableExpressionFromSet subQueryFromSet = GenerateFromSet(subQuery, db);
// The aliased name of the table
ObjectName aliasTableName = null;
if (alias != null)
{
aliasTableName = alias.Clone();
}
var source = new FromTableSubQuerySource(db.IsInCaseInsensitive, uniqueKey, subQuery, subQueryFromSet, aliasTableName);
// Add to list of subquery tables to add to command,
fromSet.AddTable(source);
}
else
{
// Else must be a standard command table,
ObjectName name = fromTable.Name;
// Resolve to full table name
ObjectName tableName = db.ResolveTableName(name);
if (!db.TableExists(tableName))
{
throw new ApplicationException("Table '" + tableName + "' was not found.");
}
ObjectName givenName = null;
if (alias != null)
{
givenName = alias.Clone();
}
// Get the ITableQueryInfo object for this table name (aliased).
ITableQueryInfo tableQueryInfo = db.GetTableQueryInfo(tableName, givenName);
var source = new FromTableDirectSource(db.IsInCaseInsensitive, tableQueryInfo, uniqueKey, givenName, tableName);
fromSet.AddTable(source);
}
} // foreach
// Set up functions, aliases and exposed variables for this from set,
// For each column being selected
foreach (SelectColumn col in selectExpression.Columns)
{
// Is this a glob? (eg. Part.* )
if (col.IsGlob)
{
// Find the columns globbed and add to the 'selectedColumns' result.
if (col.IsAll)
{
fromSet.ExposeAllColumns();
}
else
{
// Otherwise the glob must be of the form '[table name].*'
string tname = col.GlobPrefix;
ObjectName tn = ObjectName.Parse(tname);
fromSet.ExposeAllColumnsFromSource(tn);
}
}
else
{
// Otherwise must be a standard column reference. Note that at this
// time we aren't sure if a column expression is correlated and is
// referencing an outer source. This means we can't verify if the
// column expression is valid or not at this point.
// If this column is aliased, add it as a function reference to the
// TableExpressionFromSet.
var varExpression = (VariableExpression)col.Expression;
ObjectName alias = col.Alias;
ObjectName v = varExpression.VariableName;
bool aliasMatchV = (v != null && alias != null && fromSet.StringCompare(v.Name, alias.Name));
if (alias != null && !aliasMatchV)
{
fromSet.AddFunctionRef(alias.Name, col.Expression);
fromSet.ExposeVariable(alias.Clone());
}
else if (v != null)
{
ObjectName resolved = fromSet.ResolveReference(v);
fromSet.ExposeVariable(resolved ?? v);
}
else
{
string funName = col.Expression.ToString();
fromSet.AddFunctionRef(funName, col.Expression);
fromSet.ExposeVariable(ObjectName.Parse(funName));
}
}
} // for each column selected
return(fromSet);
}
/// <summary>
/// Plans an ORDER BY set.
/// </summary>
/// <param name="plan"></param>
/// <param name="orderBy"></param>
/// <param name="fromSet"></param>
/// <param name="selectedColumns"></param>
/// <remarks>
/// This is given its own function because we may want to plan
/// this at the end of a number of composite functions.
/// </remarks>
/// <returns></returns>
private static IQueryPlanNode PlanForOrderBy(IQueryPlanNode plan, IList <ByColumn> orderBy, TableExpressionFromSet fromSet, IList <SelectColumn> selectedColumns)
{
var functionTable = new ObjectName("FUNCTIONTABLE");
// Sort on the ORDER BY clause
if (orderBy.Count > 0)
{
int sz = orderBy.Count;
var orderList = new ObjectName[sz];
var ascendingList = new bool[sz];
var functionOrders = new List <Expression>();
for (int i = 0; i < sz; ++i)
{
ByColumn column = orderBy[i];
Expression exp = column.Expression;
ascendingList[i] = column.Ascending;
ObjectName v = exp.AsVariable();
if (v != null)
{
ObjectName newV = fromSet.ResolveReference(v);
if (newV == null)
{
throw new ApplicationException("Can not resolve ORDER BY variable: " + v);
}
newV = SubstituteAliasedVariable(newV, selectedColumns);
orderList[i] = newV;
}
else
{
// Otherwise we must be ordering by an expression such as
// '0 - a'.
// Resolve the expression,
exp = exp.Prepare(fromSet.ExpressionQualifier);
// Make sure we substitute any aliased columns in the order by
// columns.
exp = SubstituteAliasedVariables(exp, selectedColumns);
// The new ordering functions are called 'FUNCTIONTABLE.#ORDER-n'
// where n is the number of the ordering expression.
orderList[i] = new ObjectName(functionTable, "#ORDER-" + functionOrders.Count);
functionOrders.Add(exp);
}
}
// If there are functional orderings,
// For this we must define a new FunctionTable with the expressions,
// then order by those columns, and then use another SubsetNode
// command node.
int fsz = functionOrders.Count;
if (fsz > 0)
{
var funs = new Expression[fsz];
var fnames = new String[fsz];
for (int n = 0; n < fsz; ++n)
{
funs[n] = functionOrders[n];
fnames[n] = "#ORDER-" + n;
}
if (plan is SubsetNode)
{
// If the top plan is a QueryPlan.SubsetNode then we use the
// information from it to create a new SubsetNode that
// doesn't include the functional orders we have attached here.
var topSubsetNode = (SubsetNode)plan;
ObjectName[] mappedNames = topSubsetNode.NewColumnNames;
// Defines the sort functions
plan = new CreateFunctionsNode(plan, funs, fnames);
// Then plan the sort
plan = new SortNode(plan, orderList, ascendingList);
// Then plan the subset
plan = new SubsetNode(plan, mappedNames, mappedNames);
}
else
{
// Defines the sort functions
plan = new CreateFunctionsNode(plan, funs, fnames);
// Plan the sort
plan = new SortNode(plan, orderList, ascendingList);
}
}
else
{
// No functional orders so we only need to sort by the columns
// defined.
plan = new SortNode(plan, orderList, ascendingList);
}
}
return(plan);
}
internal static TableExpressionFromSet GenerateFromSet(TableSelectExpression selectExpression, ITableSpaceContext db)
{
// Get the 'from_clause' from the table expression
FromClause fromClause = selectExpression.From;
// Create a TableExpressionFromSet for this table expression
var fromSet = new TableExpressionFromSet(db.IsInCaseInsensitive);
// Add all tables from the 'fromClause'
foreach (FromTable fromTable in fromClause.AllTables) {
string uniqueKey = fromTable.UniqueKey;
ObjectName alias = fromTable.Alias;
// If this is a sub-command table,
if (fromTable.IsSubQueryTable) {
// eg. FROM ( SELECT id FROM Part )
TableSelectExpression subQuery = fromTable.SubSelect;
TableExpressionFromSet subQueryFromSet = GenerateFromSet(subQuery, db);
// The aliased name of the table
ObjectName aliasTableName = null;
if (alias != null)
aliasTableName = alias.Clone();
var source = new FromTableSubQuerySource(db.IsInCaseInsensitive, uniqueKey, subQuery, subQueryFromSet, aliasTableName);
// Add to list of subquery tables to add to command,
fromSet.AddTable(source);
} else {
// Else must be a standard command table,
ObjectName name = fromTable.Name;
// Resolve to full table name
ObjectName tableName = db.ResolveTableName(name);
if (!db.TableExists(tableName))
throw new ApplicationException("Table '" + tableName + "' was not found.");
ObjectName givenName = null;
if (alias != null)
givenName = alias.Clone();
// Get the ITableQueryInfo object for this table name (aliased).
ITableQueryInfo tableQueryInfo = db.GetTableQueryInfo(tableName, givenName);
var source = new FromTableDirectSource(db.IsInCaseInsensitive, tableQueryInfo, uniqueKey, givenName, tableName);
fromSet.AddTable(source);
}
} // foreach
// Set up functions, aliases and exposed variables for this from set,
// For each column being selected
foreach (SelectColumn col in selectExpression.Columns) {
// Is this a glob? (eg. Part.* )
if (col.IsGlob) {
// Find the columns globbed and add to the 'selectedColumns' result.
if (col.IsAll) {
fromSet.ExposeAllColumns();
} else {
// Otherwise the glob must be of the form '[table name].*'
string tname = col.GlobPrefix;
ObjectName tn = ObjectName.Parse(tname);
fromSet.ExposeAllColumnsFromSource(tn);
}
} else {
// Otherwise must be a standard column reference. Note that at this
// time we aren't sure if a column expression is correlated and is
// referencing an outer source. This means we can't verify if the
// column expression is valid or not at this point.
// If this column is aliased, add it as a function reference to the
// TableExpressionFromSet.
var varExpression = (VariableExpression)col.Expression;
ObjectName alias = col.Alias;
ObjectName v = varExpression.VariableName;
bool aliasMatchV = (v != null && alias != null && fromSet.StringCompare(v.Name, alias.Name));
if (alias != null && !aliasMatchV) {
fromSet.AddFunctionRef(alias.Name, col.Expression);
fromSet.ExposeVariable(alias.Clone());
} else if (v != null) {
ObjectName resolved = fromSet.ResolveReference(v);
fromSet.ExposeVariable(resolved ?? v);
} else {
string funName = col.Expression.ToString();
fromSet.AddFunctionRef(funName, col.Expression);
fromSet.ExposeVariable(ObjectName.Parse(funName));
}
}
} // for each column selected
return fromSet;
}
private static ObjectName ResolveGroupMax(TableSelectExpression expression, TableExpressionFromSet fromSet)
{
// Resolve GROUP MAX variable to a reference in this from set
ObjectName groupmaxColumn = expression.GroupMax;
if (groupmaxColumn != null) {
ObjectName v = fromSet.ResolveReference(groupmaxColumn);
if (v == null)
throw new ApplicationException("Could find GROUP MAX reference '" + groupmaxColumn + "'");
groupmaxColumn = v;
}
return groupmaxColumn;
}
/// <summary>
/// Plans an ORDER BY set.
/// </summary>
/// <param name="plan"></param>
/// <param name="orderBy"></param>
/// <param name="fromSet"></param>
/// <param name="selectedColumns"></param>
/// <remarks>
/// This is given its own function because we may want to plan
/// this at the end of a number of composite functions.
/// </remarks>
/// <returns></returns>
private static IQueryPlanNode PlanForOrderBy(IQueryPlanNode plan, IList<ByColumn> orderBy, TableExpressionFromSet fromSet, IList<SelectColumn> selectedColumns)
{
var functionTable = new ObjectName("FUNCTIONTABLE");
// Sort on the ORDER BY clause
if (orderBy.Count > 0) {
int sz = orderBy.Count;
var orderList = new ObjectName[sz];
var ascendingList = new bool[sz];
var functionOrders = new List<Expression>();
for (int i = 0; i < sz; ++i) {
ByColumn column = orderBy[i];
Expression exp = column.Expression;
ascendingList[i] = column.Ascending;
ObjectName v = exp.AsVariable();
if (v != null) {
ObjectName newV = fromSet.ResolveReference(v);
if (newV == null)
throw new ApplicationException("Can not resolve ORDER BY variable: " + v);
newV = SubstituteAliasedVariable(newV, selectedColumns);
orderList[i] = newV;
} else {
// Otherwise we must be ordering by an expression such as
// '0 - a'.
// Resolve the expression,
exp = exp.Prepare(fromSet.ExpressionQualifier);
// Make sure we substitute any aliased columns in the order by
// columns.
exp = SubstituteAliasedVariables(exp, selectedColumns);
// The new ordering functions are called 'FUNCTIONTABLE.#ORDER-n'
// where n is the number of the ordering expression.
orderList[i] = new ObjectName(functionTable, "#ORDER-" + functionOrders.Count);
functionOrders.Add(exp);
}
}
// If there are functional orderings,
// For this we must define a new FunctionTable with the expressions,
// then order by those columns, and then use another SubsetNode
// command node.
int fsz = functionOrders.Count;
if (fsz > 0) {
var funs = new Expression[fsz];
var fnames = new String[fsz];
for (int n = 0; n < fsz; ++n) {
funs[n] = functionOrders[n];
fnames[n] = "#ORDER-" + n;
}
if (plan is SubsetNode) {
// If the top plan is a QueryPlan.SubsetNode then we use the
// information from it to create a new SubsetNode that
// doesn't include the functional orders we have attached here.
var topSubsetNode = (SubsetNode)plan;
ObjectName[] mappedNames = topSubsetNode.NewColumnNames;
// Defines the sort functions
plan = new CreateFunctionsNode(plan, funs, fnames);
// Then plan the sort
plan = new SortNode(plan, orderList, ascendingList);
// Then plan the subset
plan = new SubsetNode(plan, mappedNames, mappedNames);
} else {
// Defines the sort functions
plan = new CreateFunctionsNode(plan, funs, fnames);
// Plan the sort
plan = new SortNode(plan, orderList, ascendingList);
}
} else {
// No functional orders so we only need to sort by the columns
// defined.
plan = new SortNode(plan, orderList, ascendingList);
}
}
return plan;
}
