UpdateSFCascadeReferencedExecuter


1   package com.daffodilwoods.daffodildb.server.serversystem.dmlvalidation.constraintsystem;
2   
3   import com.daffodilwoods.daffodildb.server.datadictionarysystem.*;
4   import com.daffodilwoods.daffodildb.server.serversystem.*;
5   import com.daffodilwoods.daffodildb.server.sql99.dql.iterator.*;
6   import com.daffodilwoods.daffodildb.server.sql99.expression.booleanvalueexpression.*;
7   import com.daffodilwoods.daffodildb.utils.field.*;
8   import com.daffodilwoods.database.general.*;
9   import com.daffodilwoods.database.resource.*;
10  
11  /**
12   * Objective of the class is to verify referenced constraints that have
13   * been applied on the table with update rule action as CASCADE
14   * and match option is specified as FULL or SIMPLE.
15   */
16  public class UpdateSFCascadeReferencedExecuter extends ReferencedExecuter {
17  
18    /**
19     * Constructor : used to construct a new instance of foreign constraint with
20     * the given arguments.
21     * @param referencedConstraint Value of the Referenced Constraint Descriptor
22     * having the details of the referenced constraints
23     * @param globalSess instance of _ServerSession
24     * @throws DException
25     */
26    public UpdateSFCascadeReferencedExecuter( _ReferentialConstraint referencedConstraint, _ServerSession globalSess ) throws DException {
27      globalSession = globalSess;
28      setVariables( referencedConstraint );
29    }
30  
31    /**
32     * The following method fires all the constraints having update rule with
33     * action as cascade. A private method is called to update corresponding rows
34     * of referencing table.
35     */
36    public void checkReferencedConstraints( _StatementExecutionContext sec ) throws DException {
37      populateMatchingIterator();
38      for( int i=0; i< matchingRowsPool.size(); i++ )
39          update_SimpleFull_CASCADE( i , sec );
40    }
41  
42    /**
43     * The following method updates all rows got from the iterator on child table having
44     * conditional columns as the referencing columns of the child table and corresponding
45     * values from the parent table.
46     * This method throws exception if any updation causes all the rows of child
47     * table to NON-Matching NON-NULL values in case of simple/full match.
48     */
49    private void update_SimpleFull_CASCADE( int tableIndex , _StatementExecutionContext statementExecutionContext ) throws DException {
50        ConstraintStore constraintStore = (ConstraintStore)matchingRowsPool.get(tableIndex);
51        _Iterator iterator          = constraintStore.getIterator();
52        booleanvalueexpression bve  = constraintStore.getCondition();
53        setParameterValues( iterator , bve , statementExecutionContext.getRecordVersion().getPreviousRecord() );
54        if(iterator.last()) {
55            _ServerTable serverTable = statementExecutionContext.getServerTable( (QualifiedIdentifier)sub_superTable.get(tableIndex) );
56            _StatementExecutionContext sss = getNewSEC( statementExecutionContext );
57            do {
58                int[] column = new int[referencingColumns.length];
59                Object  [] value = new Object  [referencingColumns.length];
60                for( int i=0; i<referencingColumns.length ; i++ ){
61                    column[i] = referencingColumns[i];
62                    value[i]  = ( (FieldBase) statementExecutionContext.getRecordVersion().getCurrentRecord().getObject(referencedColumns[i])).getObject();
63                }
64                serverTable.update( iterator , column, value , sss );
65            } while( iterator.previous() ) ;
66        }
67    }
68  }
69
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