/** INTERNAL: Find the alias for a given table */
public DatabaseTable aliasForTable(DatabaseTable table) {
DatabaseMapping mapping = getMapping();
if (isAttribute()
|| ((mapping != null)
&& (mapping.isAggregateObjectMapping() || mapping.isTransformationMapping()))) {
return ((DataExpression) getBaseExpression()).aliasForTable(table);
}
// "ref" and "structure" mappings, no table printed in the FROM clause, need to get the table
// alias form the parent table
if ((mapping != null) && (mapping.isReferenceMapping() || mapping.isStructureMapping())) {
DatabaseTable alias =
getBaseExpression().aliasForTable(mapping.getDescriptor().getTables().firstElement());
alias.setName(alias.getName() + "." + mapping.getField().getName());
return alias;
}
// For direct-collection mappings the alias is store on the table expression.
if ((mapping != null) && (mapping.isDirectCollectionMapping())) {
if (tableAliases != null) {
DatabaseTable aliasedTable = tableAliases.keyAtValue(table);
if (aliasedTable != null) {
return aliasedTable;
}
}
return getTable(table).aliasForTable(table);
}
return super.aliasForTable(table);
}
/** INTERNAL: Print SQL onto the stream, using the ExpressionPrinter for context */
public void printSQL(ExpressionSQLPrinter printer) {
if (isAttribute()) {
printer.printField(getAliasedField());
}
// If the mapping is a direct collection then this falls into a gray area.
// It must be treated as an attribute at this moment for it has a direct field.
// However it is not an attribute in the sense that it also represents a foreign
// reference and a mapping criteria has been added.
// For bug 2900974 these are now handled as non-attributes during normalize but
// as attributes when printing SQL.
//
if ((!isAttribute()) && (getMapping() != null) && getMapping().isDirectCollectionMapping()) {
DirectCollectionMapping directCollectionMapping = (DirectCollectionMapping) getMapping();
// The aliased table comes for free as it was a required part of the join criteria.
TableExpression table =
(TableExpression) getTable(directCollectionMapping.getReferenceTable());
DatabaseTable aliasedTable = table.aliasForTable(table.getTable());
DatabaseField aliasedField = (DatabaseField) directCollectionMapping.getDirectField().clone();
aliasedField.setTable(aliasedTable);
printer.printField(aliasedField);
}
if ((getMapping() != null) && getMapping().isNestedTableMapping()) {
DatabaseTable tableAlias = aliasForTable(new NestedTable(this));
printer.printString(tableAlias.getName());
}
}
/**
* INTERNAL: Returns the first field from each of the owned tables, used for fine-grained
* pessimistic locking.
*/
protected Vector getForUpdateOfFields() {
Vector allFields = getFields();
int expected = getTableAliases().size();
Vector firstFields = new Vector(expected);
DatabaseTable lastTable = null;
DatabaseField field = null;
int i = 0;
// The following loop takes O(n*m) time. n=# of fields. m=#tables.
// However, in the m=1 case this will take one pass only.
// Also assuming that fields are generally sorted by table, this will
// take O(n) time.
// An even faster way may be to go getDescriptor().getAdditionalPrimaryKeyFields.
while ((i < allFields.size()) && (firstFields.size() < expected)) {
field = (DatabaseField) allFields.elementAt(i++);
if ((lastTable == null) || !field.getTable().equals(lastTable)) {
lastTable = field.getTable();
int j = 0;
while (j < firstFields.size()) {
if (lastTable.equals(((DatabaseField) firstFields.elementAt(j)).getTable())) {
break;
}
j++;
}
if (j == firstFields.size()) {
firstFields.addElement(field);
}
}
}
return firstFields;
}
