/**
* Returns true if a type is a simple cast of another type. It is if the cast type is nullable and
* the cast is one of the following:
* <li>x TO x
* <li>char(n) TO varchar(m)
* <li>varchar(n) TO varchar(m)
* <li>x not null TO x nullable
*
* @param origType original type passed into the cast operand
* @param castType type the operand will be casted to
* @return true if the cast is simple
*/
private boolean isCastSimple(RelDataType origType, RelDataType castType) {
SqlTypeName origTypeName = origType.getSqlTypeName();
SqlTypeName castTypeName = castType.getSqlTypeName();
if (!(castType.isNullable())) {
return false;
}
Charset origCharset = origType.getCharset();
Charset castCharset = castType.getCharset();
if ((origCharset != null) || (castCharset != null)) {
if ((origCharset == null) || (castCharset == null)) {
return false;
}
if (!origCharset.equals(castCharset)) {
return false;
}
}
return ((origType == castType)
|| ((origTypeName == SqlTypeName.CHAR) && (castTypeName == SqlTypeName.VARCHAR))
|| ((origTypeName == SqlTypeName.VARCHAR) && (castTypeName == SqlTypeName.VARCHAR))
|| ((origTypeName == castTypeName)
&& (origType.getPrecision() == castType.getPrecision())
&& ((origTypeName != SqlTypeName.DECIMAL)
|| (origType.getScale() == castType.getScale()))
&& (!origType.isNullable() && castType.isNullable())));
}
/**
* Replaces the operands of a call. The new operands' types must match the old operands' types.
*/
public static RexCall replaceOperands(RexCall call, RexNode[] operands) {
if (call.operands == operands) {
return call;
}
for (int i = 0; i < operands.length; i++) {
RelDataType oldType = call.operands[i].getType();
RelDataType newType = operands[i].getType();
if (!oldType.isNullable() && newType.isNullable()) {
throw Util.newInternal("invalid nullability");
}
assert (oldType.toString().equals(newType.toString()));
}
return new RexCall(call.getType(), call.getOperator(), operands);
}
private void reduceCasts(RexCall outerCast) {
RexNode[] operands = outerCast.getOperands();
if (operands.length != 1) {
return;
}
RelDataType outerCastType = outerCast.getType();
RelDataType operandType = operands[0].getType();
if (operandType.equals(outerCastType)) {
removableCasts.add(outerCast);
return;
}
// See if the reduction
// CAST((CAST x AS type) AS type NOT NULL)
// -> CAST(x AS type NOT NULL)
// applies. TODO jvs 15-Dec-2008: consider
// similar cases for precision changes.
if (!(operands[0] instanceof RexCall)) {
return;
}
RexCall innerCast = (RexCall) operands[0];
if (innerCast.getOperator() != SqlStdOperatorTable.castFunc) {
return;
}
if (innerCast.getOperands().length != 1) {
return;
}
RelDataTypeFactory typeFactory = preparingStmt.getFarragoTypeFactory();
RelDataType outerTypeNullable = typeFactory.createTypeWithNullability(outerCastType, true);
RelDataType innerTypeNullable = typeFactory.createTypeWithNullability(operandType, true);
if (outerTypeNullable != innerTypeNullable) {
return;
}
if (operandType.isNullable()) {
removableCasts.add(innerCast);
}
}
