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Class org.xmlmiddleware.xmldbms.maps.Column

java.lang.Object
   |
   +----org.xmlmiddleware.xmldbms.maps.MapBase
           |
           +----org.xmlmiddleware.xmldbms.maps.Column

public class Column

extends MapBase

Column contains information about a column. The column metadata (type, length, nullability, etc.) can be set from a database or from a map document. Columns are stored in Tables, PropertyMaps, PropertyTableMaps, OrderInfos, and Keys.

Note that column values are stored in two separate objects in XML-DBMS:

• Result sets: These are JDBC ResultSet objects either passed to DBMSToDOM or generated by DBMSToDOM when transferring data from the database to XML.
• Row object: This is an intermediate object used by both DBMSToDOM and DOMToDBMS to buffer column values.

Row objects are hashtable-based and return column values by Column object. These are designed for random access.

Result sets are index-based and must be accessed in ascending order for interoperability reasons. To make this possible, each Column is given a result set index and the Table that owns the Column can return the Columns as an array sorted by result set index. This array must be used when (a) building SELECT statements to retrieve the columns in the table, and (b) when retrieving column values from those result sets.

Version:

2.0

Author:

Ronald Bourret, 1998-1999, 2001

create(String)

Create a new column.

getFormatter()

Get the column formatting object.

getLength()

Get the column length.

getName()

Get the column name.

getNullability()

Whether the column is nullable.

getPrecision()

Get the column precision.

getResultSetIndex()

Get the result set index.

getScale()

Get the column scale.

getType()

Get the column type.

isMetadataSet()

Checks whether metadata has been set for the column.

lengthExists()

Whether a length value exists.

precisionExists()

Whether a precision value exists.

resetMetadata()

Sets the metadata (type, length, etc.) to its initial state.

scaleExists()

Whether a scale value exists.

setFormatter(StringFormatter)

Set the column formatting object.

setLength(int)

Set the column length.

setNullability(int)

Set whether the column is nullable.

setPrecision(int)

Set the column precision.

setResultSetIndex(int)

Set the result set index.

setScale(int)

Set the column scale.

setType(int)

Set the column type.

 public static Column create(String columnName)

Create a new column.

Parameters:

columnName - Name of the column.

Returns:

The column.

 public final String getName()

Get the column name.

Returns:

The column name.

 public final int getResultSetIndex()

Get the result set index.

This is the index of the column value in the ResultSet. 1-based.

Returns:

The result set index.

 public void setResultSetIndex(int index)

Set the result set index.

This is the index of the column value in a JDBC ResultSet. 1-based.

Parameters:

index - The result set index.

 public final int getType()

Get the column type.

This is one of the types in the JDBC Types class.

Returns:

The column type.

 public void setType(int type)

Set the column type.

This is one of the types in the JDBC Types class. If the type is not binary or character, this method sets the length to -1.

Parameters:

type - The column type.

 public final boolean lengthExists()

Whether a length value exists.

Returns:

Whether a length value exists

 public final int getLength()

Get the column length.

Returns:

The column length. This is -1 if the length is not set.

 public void setLength(int length)

Set the column length.

Returns:

The column length.

 public final boolean precisionExists()

Whether a precision value exists.

Returns:

Whether a precision value exists

 public final int getPrecision()

Get the column precision.

Returns:

The column precision.

 public void setPrecision(int precision)

Set the column precision.

Returns:

The column precision.

 public final boolean scaleExists()

Whether a scale value exists.

Returns:

Whether a scale value exists

 public final int getScale()

Get the column scale.

Returns:

The column scale.

 public void setScale(int scale)

Set the column scale.

Returns:

The column scale.

 public final int getNullability()

Whether the column is nullable.

Returns:

DatabaseMetaData.columnNullableUnknown, .columnNullable, or .columnNoNulls.

 public void setNullability(int nullability)

Set whether the column is nullable.

Parameters:

nullability - DatabaseMetaData.columnNullableUnknown, .columnNullable, or .columnNoNulls.

 public final StringFormatter getFormatter()

Get the column formatting object.

This method returns an object that implements the org.xmlmiddleware.conversions.formatters.StringFormatter interface.

Returns:

The formatting object. For a correctly initialized Column object, this will never be null.

 public void setFormatter(StringFormatter formatter)

Set the column formatting object.

The formatting object must implement the org.xmlmiddleware.conversions.formatters.StringFormatter interface.

WARNING! Map factories must set a formatter for each column.

Parameters:

formatter - The formatting object. May not be null.

 public void resetMetadata()

Sets the metadata (type, length, etc.) to its initial state. Does not change the name.

 public boolean isMetadataSet()

Checks whether metadata has been set for the column.

Returns:

Whether metadata has been set for the column.

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