uk.co.weft.dbutil
Class ColumnDescriptor

java.lang.Object
  uk.co.weft.dbutil.ColumnDescriptor

Direct Known Subclasses:

BitColumnDescriptor, BooleanColumnDescriptor, CharacterColumnDescriptor, ClobColumnDescriptor, DateColumnDescriptor, IntegerColumnDescriptor, ObjectColumnDescriptor, RealColumnDescriptor, TimeColumnDescriptor

public abstract class ColumnDescriptor

extends java.lang.Object

A cache to hold the essential features of a database column. In effect, a hack.

Version:

$Revision: 1.21.4.3 $ This revision: $Author: simon $

Author:

Simon Brooke

Constructor Summary

ColumnDescriptor()

Method Summary

static ColumnDescriptor	createColumnDescriptor(int type, java.lang.String name, int size, int precision, int nullable) create an appropriate ColumnDescriptor for this type with these data
protected java.lang.String	format(Context c) format the value of my name in this context as a datatype of the appropriate kind for splicing into this column in a SQL query.
protected java.lang.String	formatForInsert(Context c) Deprecated. this has actually never worked as advertised and is wrong - probably for all purposes - but it has been in the toolkit so long that it is possible that some applications out there depend on its wrong behaviour, so this has not been corrected. If you are using it, consider formatForSelect( Context) instead.
protected java.lang.String	formatForMatch(Context c) Deprecated. use #formatForMatch(Context,boolean)
protected java.lang.String	formatForMatch(Context c, boolean exact) format me appropriately for use in the select operation of a match query.
protected java.lang.String	formatForSelect(Context c) format me appropriately for use in a select query or in the 'where' clause (not the 'update' clause) of an update query.
protected java.lang.String	formatForUpdate(Context c) format me appropriately for use in the 'update' clause (not the 'where' clause) of an update query.
protected java.lang.Object	genKey(Context c) generate a new unique key for me given this context
protected java.lang.Object	interpret(Context context, java.sql.ResultSet results) put into this context an interpretation of the value of my name in these results.
protected java.lang.String	quoteValue(java.lang.String s) enclose a string in single quote marks, escaping any embedded single quotes Keek this in sync with ClobColumnDescriptor.format() fun with quotes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ColumnDescriptor

public ColumnDescriptor()

Method Detail

createColumnDescriptor

public static ColumnDescriptor createColumnDescriptor(int type,
                                                      java.lang.String name,
                                                      int size,
                                                      int precision,
                                                      int nullable)
                                               throws DataFormatException

create an appropriate ColumnDescriptor for this type with these data

Throws:

DataFormatException

format

protected java.lang.String format(Context c)
                           throws DataFormatException

format the value of my name in this context as a datatype of the appropriate kind for splicing into this column in a SQL query. Specialise: default handles simple character objects.

Throws:

DataFormatException

formatForInsert

protected java.lang.String formatForInsert(Context c)
                                    throws DataFormatException

Deprecated. this has actually never worked as advertised and is wrong - probably for all purposes - but it has been in the toolkit so long that it is possible that some applications out there depend on its wrong behaviour, so this has not been corrected. If you are using it, consider formatForSelect( Context) instead.

format me appropriately for use in an insert query

Parameters:

c - context in which to find my value

Throws:

DataFormatException - if anything goes wrong (this class does not throw it but specialisations may)

formatForMatch

protected java.lang.String formatForMatch(Context c)
                                   throws DataFormatException

Deprecated. use #formatForMatch(Context,boolean)

format me appropriately for use in the select operation of a match query. For most column descriptors this is exactly the same as formatForSelect()

Throws:

DataFormatException

formatForMatch

protected java.lang.String formatForMatch(Context c,
                                          boolean exact)
                                   throws DataFormatException

format me appropriately for use in the select operation of a match query. For most column descriptors this is exactly the same as formatForSelect()

Parameters:

c - the context to match

exact - whether or not an exact match is required

Throws:

DataFormatException

formatForSelect

protected java.lang.String formatForSelect(Context c)
                                    throws DataFormatException

format me appropriately for use in a select query or in the 'where' clause (not the 'update' clause) of an update query. The difference is subtle and relates to null values, as in 'update foo set bar = null where baz is null'; this method generates the 'bar is null' part

Parameters:

c - context in which to find my value

Throws:

DataFormatException - if anything goes wrong (this class does not throw it but specialisations may)

formatForUpdate

protected java.lang.String formatForUpdate(Context c)
                                    throws DataFormatException

format me appropriately for use in the 'update' clause (not the 'where' clause) of an update query. The difference is subtle and relates to null values, as in 'update foo set bar = null where baz is null'; this method generates the 'bar = null' part

Parameters:

c - context in which to find my value

Throws:

DataFormatException - if anything goes wrong (this class does not throw it but specialisations may)

genKey

protected java.lang.Object genKey(Context c)
                           throws DataStoreException

generate a new unique key for me given this context

Throws:

throws - DataStoreException if a unique key could not be generated

DataStoreException

interpret

protected java.lang.Object interpret(Context context,
                                     java.sql.ResultSet results)
                              throws DataFormatException

put into this context an interpretation of the value of my name in these results. Return the interpretation. Specialise: default handles simple character objects.

Throws:

DataFormatException

quoteValue

protected java.lang.String quoteValue(java.lang.String s)

enclose a string in single quote marks, escaping any embedded single quotes Keek this in sync with ClobColumnDescriptor.format() fun with quotes. Keep this in sync with ColumnDescriptor.quoteValue()

Parameters:

s - the unquoted string

Returns:

the quoted string, or null if s was null

See Also:

ClobColumnDescriptor.format(Context)