k22:k22.4:k22.4.7:start

22.4.7 Class Field (gb.db)

The class represents a DB field in an (existing) DB table. You cannot create the class. All properties can only be read. The class has neither methods nor events.

22.4.7.1 Properties

The Field class has the following five properties:

Property	Data type	Description
Collation	String	Provides information on the sorting of the DB field.
Name	String	Delivers the name of the DB field.
Table	Table	Delivers the table object that contains this DB field.
Type	Integer	Delivers the type of a DB field. One of the following constants for the field data type is returned: db.Blob (-2), db.Boolean (1), db.Date (8), db.Float (7), db.Integer (4), db.Long (5), db.Serial (-1) and db.String (9).
Length	Integer	Returns the maximum length of a field. This only applies to text fields. You can determine the type of a DB field via the `Field.Type` property. If no limit has been specified for the DB text field, 0 is returned.

Table 22.4.7.1.1 : Properties of the Field class

Example

    Dim hCollection As Collection
    Dim hTable As Table, hField As Field
 
    hCollection = ["-2": "db.Blob", "-1": "db.Serial", "1": "db.Boolean", "4": "db.Integer", "5": "db.Long", "7": "db.Float", "8": "db.Date", "9": "db.String"]
 
    If DBCS.DBConnection.Tables.Exist("members") Then
 
   '-- The existing DB table `members` becomes the current DB table  
       hTable = DBCS.DBConnection.Tables["members"]
 
       Print "DBTableName: "; hTable.Name
       Print "---------------------------------------"
       Print
       For Each hField In hTable.Fields
           Print "DBField-Name: "; hField.Name
           Print "--------------------------------------"
           Print "DBField-Collation: "; IIf(hField.Collation = Null, " Not specified", hField.Collation)
           Print "DBField-Standardwert: "; IIf(hField.Default = Null, " Not specified", hField.Default)
           Print "DBField-Typ: "; hCollection[hField.Type]
           If hField.Type = db.String Then 
              If hField.Length = 0 Then 
                 Print "DBField length: No limit specified."
              Else
                 Print "DBField length: "; hField.Length
              Endif
           Endif
           Print
       Next
    Endif

This output is in the console of the IDE:

DBTableName: members
---------------------------------------

DBField-Name: m_id
--------------------------------------
DBField-Collation:  Not specified
DBField-Standard-Value:  Not specified
DBField-Type: db.Serial

DBField-Name: lastname
--------------------------------------
DBField-Collation:  Not specified
DBField-Standard-Value:  Not specified
DBField-Type: db.String
DBField length: No limit specified

DBField-Name: date
--------------------------------------
DBField-Collation:  Not specified
DBField-Standard-Value:  Not specified
DBField-Type: db.Date

DBField-Name: description
--------------------------------------
DBField-Collation:  Not specified
DBField-Standard-Value:  Not specified
DBField-Type: db.String
DBField length: No limit specified