DBColumn (Apache Empire-db Core 3.4.0 API)

java.lang.Object
- org.apache.empire.db.DBObject
- - org.apache.empire.db.DBExpr
  - - org.apache.empire.db.DBColumnExpr
    - - org.apache.empire.db.DBColumn

All Implemented Interfaces:

Column, ColumnExpr

Direct Known Subclasses:

DBCommandExpr.DBCmdColumn, DBQueryColumn, DBTableColumn, DBView.DBViewColumn
```
public abstract class DBColumn
extends DBColumnExpr
implements Column
```
This is the base class for all database columns that have a physical representation. i.e. either table or view columns (DBTableColumn oder DBViewColumn)
The column object describes a database column and thus provides metadata. Other non data model specific metadata may be added through attributes.

See Also:

DBTableColumn, DBView.DBViewColumn

Field Summary

Fields
Modifier and Type Field and Description

protected String comment

protected String name

protected Boolean quoteName

protected DBRowSet rowset
- Fields inherited from class org.apache.empire.db.DBColumnExpr
  attributes, beanPropertyName, options
- Fields inherited from class org.apache.empire.db.DBExpr
  CTX_ALIAS, CTX_ALL, CTX_DEFAULT, CTX_FULLNAME, CTX_NAME, CTX_NOPARENTHESIS, CTX_VALUE
- Fields inherited from interface org.apache.empire.data.Column
  COLATTR_CASESENSITIVE, COLATTR_CURRENCY_CODE, COLATTR_ENUMTYPE, COLATTR_FRACTION_DIGITS, COLATTR_INTEGER_DIGITS, COLATTR_MAXVALUE, COLATTR_MINLENGTH, COLATTR_MINVALUE, COLATTR_NORMCOLUMN, COLATTR_NULLTEXT, COLATTR_NUMBER_GROUPSEP, COLATTR_NUMBER_TYPE, COLATTR_REFCOLUMNS, COLATTR_REGEXP, COLATTR_SORTDESCENDING, COLATTR_SORTEXPRESSION, COLATTR_TITLE, COLATTR_TOOLTIP, COLATTR_TYPE, NUMTYPE_CURRENCY, NUMTYPE_DECIMAL, NUMTYPE_INTEGER, NUMTYPE_PERCENT

Fields
Modifier and Type	Field and Description
`protected String`	`comment`
`protected String`	`name`
`protected Boolean`	`quoteName`
`protected DBRowSet`	`rowset`

Constructor Summary

Constructors
Modifier Constructor and Description

protected DBColumn(DBRowSet rowset, String name)
Constructs a DBColumn object and set the specified parameters to this object.

Constructors
Modifier	Constructor and Description
`protected`	`DBColumn(DBRowSet rowset, String name)` Constructs a DBColumn object and set the specified parameters to this object.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addReferencedColumns(Set<DBColumn> list)` Internal function to obtain all DBColumnExpr-objects used by this expression.
`void`	`addSQL(DBSQLBuilder sql, long context)` Adds the colunm name to the SQL-Command.
`abstract Element`	`addXml(Element parent, long flags)` Appends column meta information to the parent element
`DBAliasExpr`	`coalesceColumn(Object nullValue)` Creates a column expression with coalesce and renames it to this column
`DBColumnExpr`	`decodeEnum()` Creates and returns a sql-expression that maps enum values by name or ordinal to their string representation
`DBColumnExpr`	`decodeSort(boolean defaultToEnd)` Creates and returns a sql-expression that maps enum values from name to ordinal
`boolean`	`equals(Object other)` Custom serialization for transient rowset.
`String`	`getAlias()` returns the qualified alias name for this column
`Object`	`getAttribute(String name)` Returns the value of a column attribute.
`Set<Attributes.Attribute>`	`getAttributes()` Returns all metadata attributes.
`String`	`getComment()` Returns a comment describing the column in the data scheme.
`DBDatabase`	`getDatabase()` Returns the database object to which this object belongs to.
`Entity`	`getEntity()` Returns the Entity Type Same as getRowSet()
`Class<Enum<?>>`	`getEnumType()` Returns the enum type for this column
`String`	`getFullName()` Returns the full qualified column name.
`String`	`getIdentifier()` Gets an identifier for this RowSet Object
`Class<?>`	`getJavaType()` Returns the java type for this column
`String`	`getName()` Returns the column name.
`DBColumnExpr`	`getNormalizedColumn()` Returns the normalized column for the columnExpr (if any)
`Options`	`getOptions()` Returns the list of options for this column containing all possible field values.
`Pattern`	`getRegExPattern()` Returns the maximum allowed value
`DBRowSet`	`getRowSet()` Returns DBTable, DBQuery or DBView object.
`abstract double`	`getSize()` Returns the size of the column.
`DBColumnExpr`	`getSortExpr()` Returns the sort expression for a given column If no sort expression is explicitly set then the column itself is returned The returned expression should be assigned to an DBCommand.orderBy() function.
`DBColumn`	`getUpdateColumn()` Returns itself as the underlying column.
`int`	`hashCode()`
`boolean`	`isAggregate()` Always returns false since DBColumns cannot be aggregates.
`abstract boolean`	`isAutoGenerated()` Returns true if column is a columns value is an automatically generated value
`boolean`	`isEnum()` Returns true if an enum type has been set for this column
`abstract boolean`	`isReadOnly()` Returns true if the column is read-only.
`abstract boolean`	`isRequired()` Returns true if the column is required.
`DBAliasExpr`	`qualified()` returns an expression that renames the column with its alias name
`DBColumnExpr`	`reference()` Returns a reference expression for this column This can be used to reference a parent column in a subquery
`<T extends DBColumn> T`	`setCaseInsensitive()` Sets the case sensitivity of the column to insensitive Text columns are case sensitive by default
`<T extends DBColumn> T`	`setCaseSensitive(Boolean caseSensitiv)` Sets the case sensitivity of the columnExpr
`void`	`setComment(String comment)` Sets a comment describing the current column.
`<T extends Column> T`	`setNormalizedColumn(DBColumnExpr normalizedColumn)` Sets a normalized columnExpr for this columnExpr
`<T extends DBColumn> T`	`setNumberType(String numberType)` Sets the number type to a given value
`<T extends DBColumn> T`	`setRegExPattern(String regex)` Set the regular expression to validate the columnExpr value
`<T extends DBColumn> T`	`setSortExpr(DBColumnExpr sortExpression)` Sets a sort function expression for a given column
`<T extends DBColumn> T`	`setSortExpr(String sortFunctionTemplate)` Sets a sort function template for a given column
`DBSetExpr`	`to(Object value)` Creates and returns a new DBSetExpr object.
`String`	`toString()` Override the toString method.
`abstract Object`	`validateValue(Object value)` Checks if the given value is a valid value for this column If not, an exception is thrown

Methods inherited from class org.apache.empire.db.DBColumnExpr
abs, aggregate, append, as, as, asc, avg, ceiling, cmp, coalesce, concat, concat, contains, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, decodeEnum, decodeSort, desc, divideBy, floor, format, function, getAttribute, getBeanPropertyName, getControlType, getDataType, getDefaultSortOrder, getExprFromPhrase, getExprFromPhrase, getIgnoreCaseExpr, getNumberType, getSourceColumn, getTitle, in, in, in, indexOf, indexOf, indexOf, is, isBetween, isCaseSensitive, isGreaterThan, isLessOrEqual, isLiteralValue, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, modulo, month, multiplyWith, notContains, notIn, notIn, notIn, notLike, nvl, on, parenthesis, plus, plus, prepend, replace, reverse, round, setAttribute, setBeanPropertyName, setControlType, setDefaultSortOrder, setOptions, setTitle, stringAgg, stringAgg, substring, substring, substring, substring, substring, substring, sum, toChar, toChar, trim, trimLeft, trimRight, trunc, upper, when, year

Methods inherited from class org.apache.empire.db.DBObject
checkParamNull

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.empire.data.ColumnExpr
getBeanPropertyName, getControlType, getDataType, getSourceColumn, getTitle, setAttribute

- Field Detail
  - rowset
```
protected final DBRowSet rowset
```
  - name
```
protected final String name
```
  - comment
```
protected String comment
```
  - quoteName
```
protected Boolean quoteName
```
- Constructor Detail
  - DBColumn
```
protected DBColumn(DBRowSet rowset,
                   String name)
```
    Constructs a DBColumn object and set the specified parameters to this object.
    
    Parameters:
    
    rowset - the rowset (i.e. Table or View) that this column belongs to
    
    name - the column name
- Method Detail
  - getIdentifier
```
public String getIdentifier()
```
    Gets an identifier for this RowSet Object
    
    Returns:
    
    the rowset identifier
  - equals
```
public boolean equals(Object other)
```
    Custom serialization for transient rowset. private void writeObject(ObjectOutputStream strm) throws IOException { // RowSet strm.writeObject(rowset.getDatabase().getIdentifier()); strm.writeObject(rowset.getName()); // write default strm.defaultWriteObject(); } private void readObject(ObjectInputStream strm) throws IOException, ClassNotFoundException { String dbid = String.valueOf(strm.readObject()); String rsid = String.valueOf(strm.readObject()); // find database DBDatabase dbo = DBDatabase.findByIdentifier(dbid); if (dbo==null) throw new ClassNotFoundException(dbid); // find rowset DBRowSet rso = dbo.getRowSet(rsid); if (rso==null) throw new ClassNotFoundException(dbid+"."+rsid); // set final field ClassUtils.setPrivateFieldValue(DBColumn.class, this, "rowset", rso); // read the rest strm.defaultReadObject(); }
    
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - getSize
```
public abstract double getSize()
```
    Returns the size of the column.
    
    Specified by:
    
    getSize in interface Column
    
    Returns:
    
    Returns the size of the column
  - isRequired
```
public abstract boolean isRequired()
```
    Returns true if the column is required.
    
    Specified by:
    
    isRequired in interface Column
    
    Returns:
    
    Returns true if the column is required
  - isAutoGenerated
```
public abstract boolean isAutoGenerated()
```
    Returns true if column is a columns value is an automatically generated value
    
    Specified by:
    
    isAutoGenerated in interface Column
    
    Returns:
    
    true if column is auto-generated
  - isReadOnly
```
public abstract boolean isReadOnly()
```
    Returns true if the column is read-only.
    
    Specified by:
    
    isReadOnly in interface Column
    
    Returns:
    
    Returns true if the column is read-only
  - validateValue
```
public abstract Object validateValue(Object value)
```
    Checks if the given value is a valid value for this column If not, an exception is thrown
    
    Specified by:
    
    validateValue in interface Column
    
    Parameters:
    
    value - the value to validate
    
    Returns:
    
    the value the validated and possibly converted value
  - addXml
```
public abstract Element addXml(Element parent,
                               long flags)
```
    Appends column meta information to the parent 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
  - getDatabase
```
public final 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 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(DBSQLBuilder sql,
                   long context)
```
    Adds the colunm name to the SQL-Command.
    This can be either a qualified or unqualified name depending on the context.
    
    Specified by:
    
    addSQL in class DBExpr
    
    Parameters:
    
    sql - the SQL statment
    
    context - the current SQL-Command context
  - getName
```
public String getName()
```
    Returns the column name.
    
    Specified by:
    
    getName in interface ColumnExpr
    
    Specified by:
    
    getName in class DBColumnExpr
    
    Returns:
    
    the column name
  - getRowSet
```
public DBRowSet getRowSet()
```
    Returns DBTable, DBQuery or DBView object.
    
    Specified by:
    
    getRowSet in class DBColumnExpr
    
    Returns:
    
    the DBTable, DBQuery or DBView object
  - getEntity
```
public Entity getEntity()
```
    Returns the Entity Type Same as getRowSet()
    
    Specified by:
    
    getEntity in interface Column
    
    Returns:
    
    the EntityType if any
  - getUpdateColumn
```
public DBColumn getUpdateColumn()
```
    Returns itself as the underlying column.
    
    Specified by:
    
    getUpdateColumn in interface ColumnExpr
    
    Specified by:
    
    getUpdateColumn in class DBColumnExpr
    
    Returns:
    
    the underlying column
  - isAggregate
```
public boolean isAggregate()
```
    Always returns false since DBColumns cannot be aggregates.
    
    Specified by:
    
    isAggregate in class DBColumnExpr
    
    Returns:
    
    false
  - reference
```
public DBColumnExpr reference()
```
    Returns a reference expression for this column This can be used to reference a parent column in a subquery
    
    Returns:
    
    the column value expression
  - getFullName
```
public String getFullName()
```
    Returns the full qualified column name.
    
    Returns:
    
    the full qualified column name
  - getAlias
```
public String getAlias()
```
    returns the qualified alias name for this column
    
    Returns:
    
    the alias
  - qualified
```
public DBAliasExpr qualified()
```
    returns an expression that renames the column with its alias name
    
    Overrides:
    
    qualified in class DBColumnExpr
    
    Returns:
    
    a qualified expression for this column
  - coalesceColumn
```
public DBAliasExpr coalesceColumn(Object nullValue)
```
    Creates a column expression with coalesce and renames it to this column
    
    Parameters:
    
    nullValue - the alternative value when this column is null
    
    Returns:
    
    the coalesce and alias expression
  - getAttribute
```
public Object getAttribute(String name)
```
    Description copied from class: DBColumnExpr
    
    Returns the value of a column attribute. Column attributes are used to provide metadata for a column.
    
    Specified by:
    
    getAttribute in interface ColumnExpr
    
    Overrides:
    
    getAttribute in class DBColumnExpr
    
    Parameters:
    
    name - the attribute name
    
    Returns:
    
    value of the attribute if it exists or null otherwise
    
    See Also:
    
    DBColumnExpr.getAttribute(String)
  - getAttributes
```
public Set<Attributes.Attribute> getAttributes()
```
    Returns all metadata attributes.
    
    Specified by:
    
    getAttributes in interface Column
    
    Returns:
    
    set of metadata attributes
  - getOptions
```
public Options getOptions()
```
    Description copied from class: DBColumnExpr
    
    Returns the list of options for this column containing all possible field values.
    
    Specified by:
    
    getOptions in interface ColumnExpr
    
    Overrides:
    
    getOptions in class DBColumnExpr
    
    Returns:
    
    the list of options
  - isEnum
```
public final boolean isEnum()
```
    Returns true if an enum type has been set for this column
    
    Returns:
    
    true if an enum type has been set for this column or false otherwise
  - getEnumType
```
public Class<Enum<?>> getEnumType()
```
    Returns the enum type for this column
    
    Specified by:
    
    getEnumType in interface ColumnExpr
    
    Returns:
    
    the enum type
  - getJavaType
```
public Class<?> getJavaType()
```
    Returns the java type for this column
    
    Overrides:
    
    getJavaType in class DBColumnExpr
    
    Returns:
    
    the java type
  - setCaseSensitive
```
public <T extends DBColumn> T setCaseSensitive(Boolean caseSensitiv)
```
    Sets the case sensitivity of the columnExpr
    
    Parameters:
    
    caseSensitiv - the character casing. This may be true, false or null (default)
    
    Returns:
    
    self (this)
  - setCaseInsensitive
```
public final <T extends DBColumn> T setCaseInsensitive()
```
    Sets the case sensitivity of the column to insensitive Text columns are case sensitive by default
    
    Returns:
    
    self (this)
  - setNumberType
```
public final <T extends DBColumn> T setNumberType(String numberType)
```
    Sets the number type to a given value
    
    Parameters:
    
    numberType - the number type. See Column.NUMTYPE_... constants
    
    Returns:
    
    self (this)
  - getRegExPattern
```
public Pattern getRegExPattern()
```
    Returns the maximum allowed value
    
    Returns:
    
    the minimum length
  - setRegExPattern
```
public <T extends DBColumn> T setRegExPattern(String regex)
```
    Set the regular expression to validate the columnExpr value
    
    Parameters:
    
    regex - the regular expression
    
    Returns:
    
    self (this)
  - getNormalizedColumn
```
public DBColumnExpr getNormalizedColumn()
```
    Returns the normalized column for the columnExpr (if any)
    
    Returns:
    
    the normalized column or null
  - setNormalizedColumn
```
public <T extends Column> T setNormalizedColumn(DBColumnExpr normalizedColumn)
```
    Sets a normalized columnExpr for this columnExpr
    
    Parameters:
    
    normalizedColumn - the normalized columnExpr
    
    Returns:
    
    self (this)
  - getSortExpr
```
public DBColumnExpr getSortExpr()
```
    Returns the sort expression for a given column If no sort expression is explicitly set then the column itself is returned The returned expression should be assigned to an DBCommand.orderBy() function.
    
    Returns:
    
    the sort expression or the column itself if not sort expression is set
  - setSortExpr
```
public <T extends DBColumn> T setSortExpr(DBColumnExpr sortExpression)
```
    Sets a sort function expression for a given column
    
    Parameters:
    
    sortExpression - the expression which to use for sorting
    
    Returns:
    
    self (this)
  - decodeEnum
```
public DBColumnExpr decodeEnum()
```
    Creates and returns a sql-expression that maps enum values by name or ordinal to their string representation
    
    Returns:
    
    a DBDecodeExpr object
  - decodeSort
```
public DBColumnExpr decodeSort(boolean defaultToEnd)
```
    Creates and returns a sql-expression that maps enum values from name to ordinal
    
    Parameters:
    
    defaultToEnd - flag whether to put the default item to the end
    
    Returns:
    
    a DBDecodeExpr object
  - setSortExpr
```
public <T extends DBColumn> T setSortExpr(String sortFunctionTemplate)
```
    Sets a sort function template for a given column
    
    Parameters:
    
    sortFunctionTemplate - the template which must contain a ? which will be replaced with the column name
    
    Returns:
    
    return the column
  - to
```
public DBSetExpr to(Object value)
```
    Creates and returns a new DBSetExpr object.
    
    Parameters:
    
    value - the Object value
    
    Returns:
    
    the new DBSetExpr object
    
    See Also:
    
    DBSetExpr
  - toString
```
public String toString()
```
    Override the toString method.
    
    Overrides:
    
    toString in class DBColumnExpr
    
    Returns:
    
    the table name and the column name (e.g. CUSTOMER.ID)
  - getComment
```
public String getComment()
```
    Returns a comment describing the column in the data scheme.
    
    Returns:
    
    Returns the comment.
  - setComment
```
public void setComment(String comment)
```
    Sets a comment describing the current column.
    
    Parameters:
    
    comment - the column comment

Class DBColumn

Field Summary

Fields inherited from class org.apache.empire.db.DBColumnExpr

Fields inherited from class org.apache.empire.db.DBExpr

Fields inherited from interface org.apache.empire.data.Column

Constructor Summary

Method Summary

Methods inherited from class org.apache.empire.db.DBColumnExpr

Methods inherited from class org.apache.empire.db.DBObject

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.empire.data.ColumnExpr

Field Detail

rowset

name

comment

quoteName

Constructor Detail

DBColumn

Method Detail

getIdentifier

equals

hashCode

getSize

isRequired

isAutoGenerated

isReadOnly

validateValue

addXml

getDatabase

addReferencedColumns

addSQL

getName

getRowSet

getEntity

getUpdateColumn

isAggregate

reference

getFullName

getAlias

qualified

coalesceColumn

getAttribute

getAttributes

getOptions

isEnum

getEnumType

getJavaType

setCaseSensitive

setCaseInsensitive

setNumberType

getRegExPattern

setRegExPattern

getNormalizedColumn

setNormalizedColumn

getSortExpr

setSortExpr

decodeEnum

decodeSort

setSortExpr

to

toString

getComment

setComment