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java.lang.Objectorg.apache.derby.impl.sql.compile.QueryTreeNode
org.apache.derby.impl.sql.compile.ValueNode
org.apache.derby.impl.sql.compile.CoalesceFunctionNode
public class CoalesceFunctionNode
This node represents coalesce/value function which returns the first argument that is not null. The arguments are evaluated in the order in which they are specified, and the result of the function is the first argument that is not null. The result can be null only if all the arguments can be null. The selected argument is converted, if necessary, to the attributes of the result. SQL Reference Guide for DB2 has section titled "Rules for result data types" at the following url http://publib.boulder.ibm.com/infocenter/db2help/index.jsp?topic=/com.ibm.db2.udb.doc/admin/r0008480.htm I have constructed following table based on various tables and information under "Rules for result data types" This table has FOR BIT DATA TYPES broken out into separate columns for clarity Note that are few differences between Derby and DB2 1)there are few differences between what datatypes are consdiered compatible In DB2, CHAR FOR BIT DATA datatypes are compatible with CHAR datatypes ie in addition to following table, CHAR is compatible with CHAR FOR BIT DATA, VARCHAR FOR BIT DATA and LONG VARCHAR FOR BIT DATA ie in addition to following table, VARCHAR is compatible with CHAR FOR BIT DATA, VARCHAR FOR BIT DATA and LONG VARCHAR FOR BIT DATA ie in addition to following table, LONG VARCHAR is compatible with CHAR FOR BIT DATA, VARCHAR FOR BIT DATA and LONG VARCHAR FOR BIT DATA ie in addition to following table, CHAR FOR BIT DATA is compatible with DATE, TIME, TIMESTAMP ie in addition to following table, VARCHAR FOR BIT DATA is compatible with DATE, TIME, TIMESTAMP 2)few datatypes donot have matching precision in Derby and DB2 In DB2, precision of TIME is 8. In Derby, precision of TIME is 0. In DB2, precision,scale of TIMESTAMP is 26,6. In Derby, precision of TIMESTAMP is 0,0. In DB2, precision of DOUBLE is 15. In Derby, precision of DOUBLE is 52. In DB2, precision of REAL is 23. In Derby, precision of REAL is 7. In DB2, precision calculation equation is incorrect when we have int and decimal arguments. The equation should be p=x+max(w-x,10) since precision of integer is 10 in both DB2 and Derby. Instead, DB2 has p=x+max(w-x,11) Types. S I B D R D C V L C V L C D T T B M N I E E O H A O H A O L A I I L A T G C A U A R N A R N O T M M O L E I I L B R C G R C G B E E E B L G N M L H V . H V S I E T A E A A B A A T N R L R R I R R A T C T . . M H B B P A I I R T T SMALLINT { "SMALLINT", "INTEGER", "BIGINT", "DECIMAL", "DOUBLE", "DOUBLE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, INTEGER { "INTEGER", "INTEGER", "BIGINT", "DECIMAL", "DOUBLE", "DOUBLE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, BIGINT { "BIGINT", "BIGINT", "BIGINT", "DECIMAL", "DOUBLE", "DOUBLE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, DECIMAL { "DECIMAL", "DECIMAL", "DECIMAL", "DECIMAL", "DOUBLE", "DOUBLE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, REAL { "DOUBLE", "DOUBLE", "DOUBLE", "DOUBLE", "REAL", "DOUBLE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, DOUBLE { "DOUBLE", "DOUBLE", "DOUBLE", "DOUBLE", "DOUBLE", "DOUBLE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, CHAR { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "CHAR", "VARCHAR", "LONG VARCHAR", "ERROR", "ERROR", "ERROR", "CLOB", "DATE", "TIME", "TIMESTAMP", "ERROR" }, VARCHAR { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "VARCHAR", "VARCHAR","LONG VARCHAR", "ERROR", "ERROR", "ERROR", "CLOB", "DATE", "TIME", "TIMESTAMP", "ERROR" }, LONGVARCHAR { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "LONG VARCHAR", "LONG VARCHAR", "LONG VARCHAR", "ERROR", "ERROR", "ERROR", "CLOB", "ERROR", "ERROR", "ERROR", "ERROR" }, CHAR FOR BIT { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "BIT", "BIT VARYING", "LONG BIT VARYING", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, VARCH. BIT { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "BIT VARYING", "BIT VARYING", "LONG BIT VARYING", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, LONGVAR. BIT { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "LONG BIT VARYING", "LONG BIT VARYING", "LONG BIT VARYING", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR" }, CLOB { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "CLOB", "CLOB", "CLOB", "ERROR", "ERROR", "ERROR", "CLOB", "ERROR", "ERROR", "ERROR", "ERROR" }, DATE { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "DATE", "DATE", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "DATE", "ERROR", "ERROR", "ERROR" }, TIME { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "TIME", "TIME", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "TIME", "ERROR", "ERROR" }, TIMESTAMP { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "TIMESTAMP", "TIMESTAMP", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "TIMESTAMP", "ERROR" }, BLOB { "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "ERROR", "BLOB" }
Field Summary | |
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(package private) ValueNodeList |
argumentsList
|
private int |
firstNonParameterNodeIdx
The generated method will generate code to call coalesce on this non-parameter argument. |
(package private) java.lang.String |
functionName
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Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode |
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transformed |
Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode |
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AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, isPrivilegeCollectionRequired |
Constructor Summary | |
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CoalesceFunctionNode()
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Method Summary | |
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(package private) void |
acceptChildren(Visitor v)
Accept the visitor for all visitable children of this node. |
ValueNode |
bindExpression(FromList fromList,
SubqueryList subqueryList,
java.util.Vector aggregateVector)
Binding this expression means setting the result DataTypeServices. |
boolean |
categorize(JBitSet referencedTabs,
boolean simplePredsOnly)
Categorize this predicate. |
void |
generateExpression(ExpressionClassBuilder acb,
MethodBuilder mb)
Do code generation for coalese/value |
void |
init(java.lang.Object functionName,
java.lang.Object argumentsList)
Initializer for a CalesceFunctionNode |
protected boolean |
isEquivalent(ValueNode o)
Tests if this node is equivalent to the specified ValueNode. |
ValueNode |
preprocess(int numTables,
FromList outerFromList,
SubqueryList outerSubqueryList,
PredicateList outerPredicateList)
Preprocess an expression tree. |
void |
printSubNodes(int depth)
Prints the sub-nodes of this object. |
ValueNode |
remapColumnReferencesToExpressions()
Remap all the ColumnReference s in this tree to be clones of
the underlying expression. |
java.lang.String |
toString()
Convert this object to a String. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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java.lang.String functionName
ValueNodeList argumentsList
private int firstNonParameterNodeIdx
Constructor Detail |
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public CoalesceFunctionNode()
Method Detail |
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public void init(java.lang.Object functionName, java.lang.Object argumentsList)
init
in class QueryTreeNode
functionName
- Tells if the function was called with name COALESCE or with name VALUEargumentsList
- The list of arguments to the coalesce/value functionpublic ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector) throws StandardException
bindExpression
in class ValueNode
fromList
- The FROM list for the statement.subqueryList
- The subquery list being built as we find SubqueryNodes.aggregateVector
- The aggregate vector being built as we find AggregateNodes.
StandardException
- Thrown on errorpublic void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException
generateExpression
in class ValueNode
acb
- The ExpressionClassBuilder for the class we're generatingmb
- The method the expression will go into
StandardException
- Thrown on errorpublic java.lang.String toString()
ValueNode
toString
in class ValueNode
public void printSubNodes(int depth)
printSubNodes
in class QueryTreeNode
depth
- The depth of this node in the treeprotected boolean isEquivalent(ValueNode o) throws StandardException
This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase.
Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown.
One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.:
SELECT c1+c2 FROM t1 GROUP BY c1+c2
In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below:
isEquivalent
in class ValueNode
o
- the node to compare this ValueNode against.
true
if the two nodes are equivalent,
false
otherwise.
StandardException
void acceptChildren(Visitor v) throws StandardException
acceptChildren
in class QueryTreeNode
v
- the visitor
StandardException
- on error in the visitorpublic boolean categorize(JBitSet referencedTabs, boolean simplePredsOnly) throws StandardException
categorize
in class ValueNode
referencedTabs
- JBitSet with bit map of referenced FromTablessimplePredsOnly
- Whether or not to consider method
calls, field references and conditional nodes
when building bit map
StandardException
- Thrown on errorValueNode.categorize(JBitSet, boolean)
public ValueNode preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) throws StandardException
preprocess
in class ValueNode
numTables
- Number of tables in the DML StatementouterFromList
- FromList from outer query blockouterSubqueryList
- SubqueryList from outer query blockouterPredicateList
- PredicateList from outer query block
StandardException
- Thrown on errorpublic ValueNode remapColumnReferencesToExpressions() throws StandardException
ColumnReference
s in this tree to be clones of
the underlying expression.
remapColumnReferencesToExpressions
in class ValueNode
StandardException
- if an error occurs
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Built on Thu 2011-03-10 11:54:14+0000, from revision ??? | ||||||||
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