saffron.sql
Class JdbcQuery

java.lang.Object
  |
  +--saffron.rel.Rel
        |
        +--saffron.sql.JdbcQuery

public class JdbcQuery

extends Rel

A JdbcQuery is a relational expression whose source is a SQL statement executed against a JDBC data source. It has result set calling convention.

Since:

2 August, 2002

Version:

$Id: //open/saffron/src/main/saffron/sql/JdbcQuery.java#5 $

Author:

jhyde

Nested Class Summary

Nested classes inherited from class saffron.rel.Rel

Field Summary

(package private) Expression	connectionExp The expression which yields the connection object.
(package private) SqlDialect	dialect
(package private) String	queryString For debug.
(package private) SqlSelect	sql

Fields inherited from class saffron.rel.Rel

cluster, digest, id, rowType

Constructor Summary

JdbcQuery(Cluster cluster, Type rowType, Expression connectionExp, SqlDialect dialect, SqlSelect sql)
Creates a JdbcQuery.

Method Summary

Object	clone()
Cost	computeSelfCost(Planner planner) Returns the cost of this plan (not including children).
protected Type	deriveRowType()
CallingConvention	getConvention() Returns a value from CallingConvention.
String	getQualifier()
Object	implement(Implementor implementor, int ordinal) Create a plan for this expression according to a calling convention.
void	onRegister(Planner planner) This method is called just before the expression is registered.
static void	register(Planner planner) Registers any special rules specific to this kind of relational expression.

Methods inherited from class saffron.rel.Rel

childrenAccept, computeDigest, explain, getChildExps, getCluster, getCorelVariable, getEnvironment, getId, getInput, getInputs, getOrCreateCorelVariable, getParentEnv, getQuery, getRelTypeName, getRows, getRowType, getTable, getType, getVariablesStopped, implementExp, implementExps, implementFieldAccess, implementSelf, isAccessTo, isDistinct, recomputeDigest, registerCorelVariable, replaceInput, setCorelVariable, toString

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

connectionExp

Expression connectionExp

The expression which yields the connection object.

dialect

SqlDialect dialect

sql

SqlSelect sql

queryString

String queryString

For debug. Set on register.

Constructor Detail

JdbcQuery

public JdbcQuery(Cluster cluster,
                 Type rowType,
                 Expression connectionExp,
                 SqlDialect dialect,
                 SqlSelect sql)

Creates a JdbcQuery.

Parameters:

cluster - Cluster this relational expression belongs to

Method Detail

clone

public Object clone()

Specified by:

clone in class Rel

getQualifier

public String getQualifier()

Overrides:

getQualifier in class Rel

getConvention

public CallingConvention getConvention()

Description copied from class: Rel

Returns a value from CallingConvention.

Overrides:

getConvention in class Rel

deriveRowType

protected Type deriveRowType()

Specified by:

deriveRowType in class Rel

computeSelfCost

public Cost computeSelfCost(Planner planner)

Description copied from class: Rel

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

Overrides:

computeSelfCost in class Rel

onRegister

public void onRegister(Planner planner)

Description copied from class: Rel

This method is called just before the expression is registered. The implementation of this method must at least register all child expressions.

Overrides:

onRegister in class Rel

register

public static void register(Planner planner)

Description copied from class: Rel

Registers any special rules specific to this kind of relational expression.

The planner calls this method this first time that it sees a relational expression of this class. The derived class should call Planner.addRule(saffron.opt.Rule) for each rule, and then call Rel.register(saffron.Planner) on its base class.

implement

public Object implement(Implementor implementor,
                        int ordinal)

Description copied from class: Rel

Create a plan for this expression according to a calling convention.

Overrides:

implement in class Rel

Parameters:

implementor - implementor

ordinal - indicates our position in the pre-, in- and postfix walk over the tree; ordinal is -1 when called from the parent, and i when called from the i^th child.