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

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.DBConcatExpr
All Implemented Interfaces:
Serializable, ColumnExpr

public class DBConcatExpr
extends DBColumnExpr

This class is used for performing string concatenation in SQL

There is no need to explicitly create instances of this class.
Instead use DBColumnExpr.append(Object)

See Also:
Serialized Form

Field Summary
protected  DBColumnExpr left
           
protected  Object right
           
 
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
DBConcatExpr(DBColumnExpr left, Object right)
          Constructs a new DBConcatExpr 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 concatenate a specified column with a specified value sets the column with a specified value to the SQL-Command.
 Element addXml(Element parent, long flags)
          Add a description of this column with relevant metadata to the supplied parent XML Element.
 boolean equals(Object other)
           
 DBDatabase getDatabase()
          Returns the database object to which this object belongs to.
 DataType getDataType()
          Returns the data type: DataType.TEXT
 String getName()
          Returns the column name for this column expression.
 DBColumn getUpdateColumn()
          Returns the underlying physical column which may be used for updates.
 boolean isAggregate()
          Always returns false since a concat expression 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, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

left

protected final DBColumnExpr left

right

protected final Object right
Constructor Detail

DBConcatExpr

public DBConcatExpr(DBColumnExpr left,
                    Object right)
Constructs a new DBConcatExpr object set the specified parameters to this object.

Parameters:
left - the left column for this concatenation
right - the right column for this concatenation
Method Detail

getDatabase

public DBDatabase getDatabase()
Description copied from class: DBObject
Returns the database object to which this object belongs to. For the database object itself this function will return the this pointer.

Specified by:
getDatabase in class DBObject
Returns:
the database object

getDataType

public DataType getDataType()
Returns the data type: DataType.TEXT

Specified by:
getDataType in interface ColumnExpr
Specified by:
getDataType in class DBColumnExpr
Returns:
DataType.TEXT
See Also:
DataType

getName

public String getName()
Description copied from class: DBColumnExpr
Returns the column name for this column expression. The name must contain only alphanumeric characters and the underscore. For SQL functions this name may be generated. However subsequent calls to this function for the same object instance must return the same string.

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

addXml

public Element addXml(Element parent,
                      long flags)
Description copied from class: DBColumnExpr
Add a description of this column with relevant metadata to the supplied parent XML Element.

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()
Description copied from class: DBColumnExpr
Returns the underlying physical column which may be used for updates. For functions involving none or more than one physical column this function returns null.

Specified by:
getUpdateColumn in class DBColumnExpr
Returns:
the column to be used for updates if any.

isAggregate

public boolean isAggregate()
Always returns false since a concat expression cannot be an aggregate.

Specified by:
isAggregate in class DBColumnExpr
Returns:
false

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 concatenate a specified column with a specified value sets the column with a specified value to the SQL-Command.

Specified by:
addSQL in class DBExpr
Parameters:
buf - the SQL statment
context - the current SQL-Command context

equals

public boolean equals(Object other)
Overrides:
equals in class Object


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