pack-priv abstract Class SetOperatorNode

Overrides org.apache.derby.impl.sql.compile.TableOperatorNode.bindResultColumns.

Bind the result columns of this ResultSetNode when there is no base table to bind them to. This is useful for SELECT statements, where the result columns get their types from the expressions that live under them.

Parameters

fromListParam:FromList

FromList to use/append to.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.TableOperatorNode.bindResultColumns.

Bind the result columns for this ResultSetNode to a base table. This is useful for INSERT and UPDATE statements, where the result columns get their types from the table being updated or inserted into. If a result column list is specified, then the verification that the result column list does not contain any duplicates will be done when binding them by name.

Parameters

targetTableDescriptor:TableDescriptor

The TableDescriptor for the table being updated or inserted into

targetColumnList:ResultColumnList

For INSERT statements, the user does not have to supply column names (for example, "insert into t values (1,2,3)". When this parameter is null, it means that the user did not supply column names, and so the binding should be done based on order. When it is not null, it means do the binding by name, not position.

statement:DMLStatementNode

Calling DMLStatementNode (Insert or Update)

fromListParam:FromList

FromList to use/append to.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.bindTargetExpressions.

Bind the expressions in the target list. This means binding the sub-expressions, as well as figuring out what the return type is for each expression. This is useful for EXISTS subqueries, where we need to validate the target list before blowing it away and replacing it with a SELECT true.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.TableOperatorNode.bindUntypedNullsToResultColumns.

Bind the result columns of a table constructor to the types in the given ResultColumnList. Use when inserting from a table constructor, and there are nulls in the values clauses.

Parameters

rcl:ResultColumnList

The ResultColumnList with the types to bind to

Annotations

@Override

Exceptions

StandardException:

Thrown on error.

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.ensurePredicateList.

Ensure that the top of the RSN tree has a PredicateList.

Parameters

numTables:int

The number of tables in the query.

Returns:ResultSetNode

ResultSetNode A RSN tree with a node which has a PredicateList on top.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.flattenableInFromSubquery.

Evaluate whether or not the subquery in a FromSubquery is flattenable. Currently, a FSqry is flattenable if all of the following are true: o Subquery is a SelectNode. (ie, not a RowResultSetNode or a UnionNode) o It contains no top level subqueries. (RESOLVE - we can relax this) o It does not contain a group by or having clause o It does not contain aggregates.

Parameters

fromList:FromList

The outer from list

Returns:boolean

boolean Whether or not the FromSubquery is flattenable.

Annotations

@Override

Overrides org.apache.derby.impl.sql.compile.TableOperatorNode.getFromTableByName.

Determine whether or not the specified name is an exposed name in the current query block.

Parameters

name:String

The specified name to search for as an exposed name.

schemaName:String

Schema name, if non-null.

exactMatch:boolean

Whether or not we need an exact match on specified schema and table names or match on table id.

Returns:FromTable

The FromTable, if any, with the exposed name.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Retrieve the list of optimizable predicates that are targeted for the left child. Create a new (empty) list if the list is null.

Returns:String

the operator name: "UNION", "INTERSECT", or "EXCEPT"

Get the parameter types from the given RowResultSetNode into the given array of types. If an array position is already filled in, don't clobber it.

Parameters

types:DataTypeDescriptor[]

The array of types to fill in

rrsn:RowResultSetNode

The RowResultSetNode from which to take the param types

Returns:int

The number of new types found in the RowResultSetNode

Retrieve the list of optimizable predicates that are targeted for the right child. Create a new (empty) list if the list is null.

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.performMaterialization.

Return whether or not to materialize this ResultSet tree.

Returns:boolean

Whether or not to materialize this ResultSet tree. would return valid results.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.TableOperatorNode.preprocess.

Put a ProjectRestrictNode on top of each FromTable in the FromList. ColumnReferences must continue to point to the same ResultColumn, so that ResultColumn must percolate up to the new PRN. However, that ResultColumn will point to a new expression, a VirtualColumnNode, which points to the FromTable and the ResultColumn that is the source for the ColumnReference. (The new PRN will have the original of the ResultColumnList and the ResultColumns from that list. The FromTable will get shallow copies of the ResultColumnList and its ResultColumns. ResultColumn.expression will remain at the FromTable, with the PRN getting a new VirtualColumnNode for each ResultColumn.expression.) We then project out the non-referenced columns. If there are no referenced columns, then the PRN's ResultColumnList will consist of a single ResultColumn whose expression is 1.

Parameters

numTables:int

Number of tables in the DML Statement

gbl:GroupByList

The group by list, if any

fromList:FromList

The from list, if any

Returns:ResultSetNode

The preprocessed ResultSetNode that can be optimized

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.TableOperatorNode.printSubNodes.

Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Parameters

depth:int

The depth of this node in the tree

Annotations

@Override

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.pushOffsetFetchFirst.

Push down the offset and fetch first parameters, if any, to this node.

Parameters

offset:ValueNode

the OFFSET, if any

fetchFirst:ValueNode

the OFFSET FIRST, if any

hasJDBClimitClause:boolean

true if the clauses were added by (and have the semantics of) a JDBC limit clause

Annotations

@Override

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.pushOrderByList.

Push the order by list down from the cursor node into its child result set so that the optimizer has all of the information that it needs to consider sort avoidance.

Parameters

orderByList:OrderByList

The order by list

Annotations

@Override

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.replaceOrForbidDefaults.

Doc from org.apache.derby.impl.sql.compile.ResultSetNode.replaceOrForbidDefaults.

Replace any DEFAULTs with the associated tree for the default if allowed, or flag (when inside top level set operator nodes). Subqueries are checked for illegal DEFAULTs elsewhere.

Parameters

ttd:TableDescriptor

The TableDescriptor for the target table.

tcl:ResultColumnList

The RCL for the target table.

allowDefaults:boolean

true if allowed

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Set the type of each ? parameter in the given RowResultSetNode according to its ordinal position in the given array of types.

Parameters

types:DataTypeDescriptor[]

An array of types containing the proper type for each ? parameter, by ordinal position.

rrsn:RowResultSetNode

A RowResultSetNode that could contain ? parameters whose types need to be set.

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.setResultToBooleanTrueNode.

Set the result column for the subquery to a boolean true, Useful for transformations such as changing: where exists (select ... from ...) to: where (select true from ...) NOTE: No transformation is performed if the ResultColumn.expression is already the correct boolean constant. This method is used during binding of EXISTS predicates to map a subquery's result column list into a single TRUE node. For SELECT and VALUES subqueries this transformation is pretty straightforward. But for set operators (ex. INTERSECT) we have to do some extra work. To see why, assume we have the following query: select * from ( values 'BAD' ) as T where exists ((values 1) intersect (values 2)) If we treated the INTERSECT in this query the same way that we treat SELECT/VALUES subqueries then the above query would get transformed into: select * from ( values 'BAD' ) as T where ((values TRUE) intersect (values TRUE)) Since both children of the INTERSECT would then have the same value, the result of set operation would be a single value (TRUE), which means the WHERE clause would evaluate to TRUE and thus the query would return one row with value 'BAD'. That would be wrong. To avoid this problem, we internally wrap this SetOperatorNode inside a "SELECT *" subquery and then we change the new SelectNode's result column list (as opposed to *this* nodes' result column list) to a singe boolean true node: select * from ( values 'BAD' ) as T where SELECT TRUE FROM ((values 1) intersect (values 2)) In this case the left and right children of the INTERSECT retain their values, which ensures that the result of the intersect operation will be correct. Since (1 intersect 2) is an empty result set, the internally generated SELECT node will return zero rows, which in turn means the WHERE predicate will return NULL (an empty result set from a SubqueryNode is treated as NULL at execution time; see impl/sql/execute/AnyResultSet). Since NULL is not the same as TRUE the query will correctly return zero rows. DERBY-2370.

Parameters

onlyConvertAlls:boolean

Boolean, whether or not to just convert *'s

Returns:ResultSetNode

Doc from org.apache.derby.impl.sql.compile.ResultSetNode.setResultToBooleanTrueNode.

ResultSetNode whose resultColumn was transformed; defaults to "this" here, but can be overridden by subclasses.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.ResultSetNode.verifySelectStarSubquery.

Verify that a SELECT * is valid for this type of subquery.

Parameters

outerFromList:FromList

The FromList from the outer query block(s)

subqueryType:int

The subquery type

Annotations

@Override

Exceptions

StandardException:

Thrown on error