org.apache.empire.db.expr.compare
Class DBExistsExpr

java.lang.Object
  extended by org.apache.empire.db.DBObject
      extended by org.apache.empire.db.DBExpr
          extended by org.apache.empire.db.expr.compare.DBCompareExpr
              extended by org.apache.empire.db.expr.compare.DBExistsExpr
All Implemented Interfaces:
Serializable

public class DBExistsExpr
extends DBCompareExpr

This class is used for building up the SQL-Command for the EXISTS syntax.

See Also:
Serialized Form

Field Summary
 DBCommandExpr cmd
           
 DBCompareExpr compareExpr
           
 
Fields inherited from class org.apache.empire.db.DBExpr
CTX_ALIAS, CTX_ALL, CTX_DEFAULT, CTX_FULLNAME, CTX_NAME, CTX_NOPARENTHESES, CTX_VALUE
 
Constructor Summary
DBExistsExpr(DBCommandExpr cmd)
          Constructs a DBExistsExpr object set the specified parameters to this object.
DBExistsExpr(DBCommandExpr cmd, DBCompareExpr compareExpr)
          Constructs a DBExistsExpr object set the specified parameters to this object.
 
Method Summary
 void addReferencedColumns(Set<DBColumn> list)
          Internal function to obtain all DBColumnExpr-objects used by this expression.
 void addSQL(StringBuilder buf, long context)
          Creates the SQL-Command.
 DBDatabase getDatabase()
          Returns the current DBDatabase object.
 boolean isMutuallyExclusive(DBCompareExpr other)
          Returns wheter the constraint should replace another one or not.
 
Methods inherited from class org.apache.empire.db.expr.compare.DBCompareExpr
and, not, or
 
Methods inherited from class org.apache.empire.db.DBExpr
getObjectValue, getValueClass
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

cmd

public final DBCommandExpr cmd

compareExpr

public final DBCompareExpr compareExpr
Constructor Detail

DBExistsExpr

public DBExistsExpr(DBCommandExpr cmd)
Constructs a DBExistsExpr object set the specified parameters to this object.

Parameters:
cmd - the DBCommandExpr object

DBExistsExpr

public DBExistsExpr(DBCommandExpr cmd,
                    DBCompareExpr compareExpr)
Constructs a DBExistsExpr object set the specified parameters to this object.

Parameters:
cmd - the DBCommandExpr object
compareExpr - The expression to append to the end of the exists statement
Method Detail

getDatabase

public DBDatabase getDatabase()
Returns the current DBDatabase object.

Specified by:
getDatabase in class DBObject
Returns:
the current DBDatabase object

addReferencedColumns

public void addReferencedColumns(Set<DBColumn> list)
Description copied from class: DBExpr
Internal function to obtain all DBColumnExpr-objects used by this expression.

Specified by:
addReferencedColumns in class DBExpr
Parameters:
list - list to which all used column expressions must be added
See Also:
DBExpr.addReferencedColumns(Set)

addSQL

public void addSQL(StringBuilder buf,
                   long context)
Creates the SQL-Command.

Specified by:
addSQL in class DBExpr
Parameters:
buf - the SQL-Command
context - the current SQL-Command context (CTX_DEFAULT, CTX_SELECT, CTX_NAME, CTX_VALUE)

isMutuallyExclusive

public boolean isMutuallyExclusive(DBCompareExpr other)
Returns wheter the constraint should replace another one or not.

Specified by:
isMutuallyExclusive in class DBCompareExpr
Returns:
true it the constraints are mutually exclusive or false otherwise


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