/**
* @param expr
* @param tables
*/
void getTablesForExpression(AbstractExpression expr, HashSet<Table> tables) {
List<TupleValueExpression> tves = ExpressionUtil.getTupleValueExpressions(expr);
for (TupleValueExpression tupleExpr : tves) {
String tableName = tupleExpr.getTableName();
Table table = getTableFromDB(tableName);
tables.add(table);
}
}
// Even though this function applies generally to expressions and tables and not just to TVEs as
// such,
// this function is somewhat TVE-related because TVEs DO represent the points where expression
// trees
// depend on tables.
public static boolean isOperandDependentOnTable(AbstractExpression expr, Table table) {
for (TupleValueExpression tve : ExpressionUtil.getTupleValueExpressions(expr)) {
// TODO: This clumsy testing of table names regardless of table aliases is
// EXACTLY why we can't have nice things like self-joins.
if (table.getTypeName().equals(tve.getTableName())) {
return true;
}
}
return false;
}
/**
* Parse the scan_columns element out of the HSQL-generated XML. Fills scanColumns with a list of
* the columns used in the plan, hashed by table name.
*
* @param columnsNode
*/
void parseScanColumns(VoltXMLElement columnsNode) {
scanColumns = new HashMap<String, ArrayList<SchemaColumn>>();
for (VoltXMLElement child : columnsNode.children) {
assert (child.name.equals("columnref"));
AbstractExpression col_exp = parseExpressionTree(child);
// TupleValueExpressions are always specifically typed,
// so there is no need for expression type specialization, here.
assert (col_exp != null);
assert (col_exp instanceof TupleValueExpression);
TupleValueExpression tve = (TupleValueExpression) col_exp;
SchemaColumn col =
new SchemaColumn(tve.getTableName(), tve.getColumnName(), tve.getColumnAlias(), col_exp);
ArrayList<SchemaColumn> table_cols = null;
if (!scanColumns.containsKey(col.getTableName())) {
table_cols = new ArrayList<SchemaColumn>();
scanColumns.put(col.getTableName(), table_cols);
}
table_cols = scanColumns.get(col.getTableName());
table_cols.add(col);
}
}
