org.apache.empire.db.expr.column
Class DBValueExpr

java.lang.Object
  extended by org.apache.empire.db.DBObject
      extended by org.apache.empire.db.DBExpr
          extended by org.apache.empire.db.DBColumnExpr
              extended by org.apache.empire.db.expr.column.DBValueExpr
All Implemented Interfaces:
Serializable, ColumnExpr

public class DBValueExpr
extends DBColumnExpr

This class is used for declaring constant values in SQL.

There is no need to explicitly create instances of this class.
Instead use DBDatabase.getValueExpr(String) or one of it's overloads

See Also:
Serialized Form

Field Summary
 DBColumnExpr column
           
 DBDatabase db
           
 DataType type
           
 Object value
           
 
Fields inherited from class org.apache.empire.db.DBColumnExpr
attributes, beanPropertyName, DBCOLATTR_TITLE, DBCOLATTR_TYPE, options
 
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
DBValueExpr(DBColumnExpr col, Object value)
          Construct a new DBValueExpr object set the specified parameters to this object.
DBValueExpr(DBDatabase db, Object value, DataType type)
          Constructs a new DBValueExpr 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.
 Element addXml(Element parent, long flags)
          this helper function calls the DBColumnExpr.addXML(Element, long) method
 DBDatabase getDatabase()
          Returns the current DBDatabase object.
 DataType getDataType()
          Returns the data type of the DBColumnExpr object.
 String getName()
          Returns the column name.
 DBColumn getUpdateColumn()
          Returns null.
 boolean isAggregate()
          Always returns false since value expressions cannot be an aggregate.
 
Methods inherited from class org.apache.empire.db.DBColumnExpr
abs, append, as, as, asc, avg, cmp, coalesce, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, desc, detectDataType, divideBy, getAttribute, getBeanPropertyName, getControlType, getExprFromPhrase, getExprFromPhrase, getOptions, getSourceColumn, getTitle, in, indexOf, indexOf, indexOf, is, isBetween, isGreaterThan, isLessOrEqual, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, month, multiplyWith, notIn, notLike, nvl, parenthesis, plus, plus, replace, reverse, round, setAttribute, setBeanPropertyName, setControlType, setOptions, setTitle, substring, substring, substring, substring, substring, substring, sum, toChar, toChar, trim, trimLeft, trimRight, trunc, upper, when, year
 
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

db

public final DBDatabase db

value

public final Object value

type

public final DataType type

column

public final DBColumnExpr column
Constructor Detail

DBValueExpr

public DBValueExpr(DBDatabase db,
                   Object value,
                   DataType type)
Constructs a new DBValueExpr object.

Parameters:
db - the database
value - the value for this constant
type - the data type for this constant

DBValueExpr

public DBValueExpr(DBColumnExpr col,
                   Object value)
Construct a new DBValueExpr object set the specified parameters to this object.

Parameters:
col - the column
value - the value
Method Detail

getDatabase

public DBDatabase getDatabase()
Returns the current DBDatabase object.

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

getDataType

public DataType getDataType()
Returns the data type of the DBColumnExpr object.

Specified by:
getDataType in interface ColumnExpr
Specified by:
getDataType in class DBColumnExpr
Returns:
the data type
See Also:
DataType

getName

public String getName()
Returns the column name.

Specified by:
getName in interface ColumnExpr
Specified by:
getName in class DBColumnExpr
Returns:
the column name

addXml

public Element addXml(Element parent,
                      long flags)
this helper function calls the DBColumnExpr.addXML(Element, long) method

Specified by:
addXml in class DBColumnExpr
Parameters:
parent - the parent element to which to append the column description
flags - currently not used
Returns:
the newly created child element

getUpdateColumn

public DBColumn getUpdateColumn()
Returns null.

Specified by:
getUpdateColumn in class DBColumnExpr
Returns:
null

isAggregate

public boolean isAggregate()
Always returns false since value expressions cannot be an aggregate.

Specified by:
isAggregate in class DBColumnExpr
Returns:
false

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

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)


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