DataColumn

Overview

A DataColumn represents the definition of an individual field in a DataTable. Descendant classes, such as CalculatedDataColumn and LookupDataColumn exist for more specialized field types, but a regular DataColumn represents a real field that is physically stored as part of the data table.

You will not usually create or deal with DataColumn yourself, but work with fields through the properties exposed by DataTable and DataRow. If necessary, you can query a DataTable for a list of all defined columns via its getColumns method, and inspect them individually as DataColumn or subclass thereof.

Location

 

constructor

Emty constructor that creates an instance of the DataColumn

 

constructor

 

DataColumn()

constructor (String)

Creates an instance of a column with the given name. Default data type is String.

 

constructor(aName: String)

 

DataColumn(String aName)

Parameters:

  • aName: Given column name.

constructor (String, Class)

Creates an instance of a column with the given name and value type.

 

constructor(aName: String; aDataType: Class)

 

DataColumn(String aName, Class aDataType)

Parameters:

  • aName: Given column name.
  • aDataType: Given column data type.

AllowNull

 

property AllowNull: Boolean read write;

 

Boolean AllowNull { __get; __set; }

AutoInc

 

property AutoInc: Boolean read write;

 

Boolean AutoInc { __get; __set; }

AutoIncStart

 

property AutoIncStart: Int64 read write;

 

Int64 AutoIncStart { __get; __set; }

AutoIncStep

 

property AutoIncStep: Int64 read write;

 

Int64 AutoIncStep { __get; __set; }

Caption

 

property Caption: String read write;

 

String Caption { __get; __set; }

clone

Creates a clone of the current DataColumn.

 

method clone: DataColumn

 

DataColumn clone()

ColumnName

 

property ColumnName: String read write;

 

String ColumnName { __get; __set; }

DataType

 

property DataType: Class read write;

 

Class DataType { __get; __set; }

DefaultValue

 

property DefaultValue: Object read write;

 

Object DefaultValue { __get; __set; }

intSetReadOnly  protected

 

method intSetReadOnly(aValue: Boolean)

 

void intSetReadOnly(Boolean aValue)

Parameters:

  • aValue:

MaxLength

 

property MaxLength: Integer read write;

 

Integer MaxLength { __get; __set; }

Ordinal

 

property Ordinal: Integer read write;

 

Integer Ordinal { __get; __set; }

Properties

 

property Properties: PropertyCollection read;

 

PropertyCollection Properties { __get; }

ReadOnly

 

property ReadOnly: Boolean read write;

 

Boolean ReadOnly { __get; __set; }

setAutoInc

Helper method to set incrementation mode of the column. Allows to enable autoincrementation, set its start value and increment value in one call.

 

method setAutoInc(aValue: Boolean; aStart: Long; aStep: Long)

 

void setAutoInc(Boolean aValue, Long aStart, Long aStep)

Parameters:

  • aValue: true - if auto inc enabled; otherwise - false.
  • aStart: The start value of values' incrementation
  • aStep: The increment/step value by which row's value wil be increased

Table

 

property Table: DataTable read write;

 

DataTable Table { __get; __set; }

 

AllowNull

 

property AllowNull: Boolean read write;

 

Boolean AllowNull { __get; __set; }

AutoInc

 

property AutoInc: Boolean read write;

 

Boolean AutoInc { __get; __set; }

AutoIncStart

 

property AutoIncStart: Int64 read write;

 

Int64 AutoIncStart { __get; __set; }

AutoIncStep

 

property AutoIncStep: Int64 read write;

 

Int64 AutoIncStep { __get; __set; }

Caption

 

property Caption: String read write;

 

String Caption { __get; __set; }

ColumnName

 

property ColumnName: String read write;

 

String ColumnName { __get; __set; }

DataType

 

property DataType: Class read write;

 

Class DataType { __get; __set; }

DefaultValue

 

property DefaultValue: Object read write;

 

Object DefaultValue { __get; __set; }

MaxLength

 

property MaxLength: Integer read write;

 

Integer MaxLength { __get; __set; }

Ordinal

 

property Ordinal: Integer read write;

 

Integer Ordinal { __get; __set; }

Properties

 

property Properties: PropertyCollection read;

 

PropertyCollection Properties { __get; }

ReadOnly

 

property ReadOnly: Boolean read write;

 

Boolean ReadOnly { __get; __set; }

Table

 

property Table: DataTable read write;

 

DataTable Table { __get; __set; }

 

constructor

Emty constructor that creates an instance of the DataColumn

 

constructor

 

DataColumn()

constructor (String)

Creates an instance of a column with the given name. Default data type is String.

 

constructor(aName: String)

 

DataColumn(String aName)

Parameters:

  • aName: Given column name.

constructor (String, Class)

Creates an instance of a column with the given name and value type.

 

constructor(aName: String; aDataType: Class)

 

DataColumn(String aName, Class aDataType)

Parameters:

  • aName: Given column name.
  • aDataType: Given column data type.

clone

Creates a clone of the current DataColumn.

 

method clone: DataColumn

 

DataColumn clone()

intSetReadOnly  protected

 

method intSetReadOnly(aValue: Boolean)

 

void intSetReadOnly(Boolean aValue)

Parameters:

  • aValue:

setAutoInc

Helper method to set incrementation mode of the column. Allows to enable autoincrementation, set its start value and increment value in one call.

 

method setAutoInc(aValue: Boolean; aStart: Long; aStep: Long)

 

void setAutoInc(Boolean aValue, Long aStart, Long aStep)

Parameters:

  • aValue: true - if auto inc enabled; otherwise - false.
  • aStart: The start value of values' incrementation
  • aStep: The increment/step value by which row's value wil be increased

Descendants

See Also