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);
}
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;
}
