The Columns wizard allows you to specify column properties for OpenEdge databases. You use it to specify the properties of a new column or to change the properties of an existing column.
Start the Columns wizard by clicking Add
Column
or Edit
Column
. Both are available
from context menus in the
DB Structure view and from the OpenEdge
Table tab of the DB Details view.
The Columns wizard allows you to specify the following properties:
| Name |
A column name that is unique within the selected table. A column name must start with a letter and can contain only letters, digits, or the following symbols: #, $, %, -, _, or &. Note: The Name field is disabled while
editing a partition key column since a partition key column
cannot be renamed.
|
| Data Type | A valid OpenEdge data type. The data types
include CHARACTER, DATE, DECIMAL, INTEGER, INT64, LOGICAL, DATETIME,
DATETIME-TZ, RAW, RECID, BLOB, and CLOB. The properties available in
the Columns wizard change based
on the choice of data type. You cannot change the data type of an
existing column except to change from integer to INT64. Note: Changing the data type from INTEGER to INT64 is
irreversible. The Data Type field is
disabled while editing a column since the data type of a column
cannot be changed.
|
| Size | Maximum size (SQLWidth property) for the column. You can change the size of an existing column for these data types only: CHARACTER, DECIMAL, CLOB, BLOB, and RAW. |
| Scale | (Available only if Data Type is DECIMAL.) Maximum number of digits to the right of the decimal point. You cannot change the scale of an existing column. The scale defaults to the number of integers defined to the right of the decimal point in the format. |
| Format | Display format for data in the column. You can choose character, date, logical, and numeric format options to determine how data is displayed on screens or in printed reports. This field is followed by a Field String Attribute field for controlling text preferences and space allocation. Each data type has a default format defined in the DB Navigator preferences. |
| Label | The column heading that
appears on screens or in printed reports to identify the column. The
Unknown value (?) causes the string that appears in Name to be used.
This field is followed by a Field String Attribute field
for controlling text preferences and space allocation. Note: If you
use ? as a label, precede it with a backslash. For example:
\?.
|
| Col Label | A heading that appears when a program lists data in columns. ? causes the string that appears in Label to be used. This field is followed by a Field String Attribute field for controlling text preferences and space allocation. |
| Init Value | The initial value, based on data type, for the column. This field is followed by a Field String Attribute field for controlling text preferences and space allocation. |
| Order | A number that indicates
position of this column in relation to other columns in the table.
Note: This order is used only when you display schema in an ABL
client session. The order is not reflected in the DB
Structure view, which displays columns in order
of creation.
By default, the order number for the first
column is 10. Order numbers for subsequent columns are automatically
incremented by 10. You can, however, modify the default order number
to reposition the column. For example, if you want to position a new
column between the first column (order number 10) and the second
column (order number 20), you can set the order number to 15 for the
new column. |
| Extent | When selected, creates an array field and allows you to specify the number of elements. |
| Description | A description of the contents or purpose of the column for documentation purposes. |
| Help Text | A help message that appears whenever a user is prompted to input data. This field is followed by a Field String Attribute field for controlling text preferences and space allocation. |
| View As | Specifies a UI widget
(fill-in field, combo box, etc.) that represents the column on the
screen. The widget you can use depends on the data type. See the
VIEW-AS phrase in OpenEdge Development: ABL Reference for more
information. Note: You can find OpenEdge manuals in the Product Documentation
section of the Progress Software Developer's Network Web
site.
|
| Validation | An expression that defines valid data for the column (for example custnum>0). |
| Val Msg | The error message that is displayed when the user attempts to enter invalid data. This field is followed by a Field String Attribute field for controlling text preferences and space allocation. |
| Case sensitive | When selected, defines character columns as case-sensitive. |
| Mandatory | When selected, makes the column mandatory. That is, it cannot have the Unknown value (?). |
| ax Size | (For BLOB or CLOB data types only) A value that indicates the maximum size for the column. You must indicate whether the value expresses Bytes, KiloBytes, MegaBytes, or GigaBytes. |
| Code page | (For CLOB data types only) Specifies a code page. A code page is a table that assigns a numeric value to each element in a collection of letters, numbers, punctuation, control codes, and other characters. The assignment is one-to-one: no two characters are assigned the same numeric value, and no two numeric values are assigned the same character. |
| Collation | (For CLOB data types only) Specifies collation preference. A collation is a set of rules that determine how character data is ordered. OpenEdge provides a set of collation tables to sort and compare character data. |
| String Attribute field | Controls text preferences and how much space the ABL compiler allocates for a string within an r-code text segment. |
The Columns wizard also has a tree view that shows the existing columns in the currently selected table. The following buttons are below the tree view:
| Copy | Allows one or more columns to be created from other columns in any table. Upon selecting a column and then selecting OK, the column information is copied into the Column tab folder view and the node is added to the tree view. If a column by the same name already exists in the table, a message is displayed and the column is renamed to be unique. |
| Remove | Removes selected columns from the tree
view. Note: The Remove option is disabled
while editing a partition key column, since a partition key
cannot be removed.
|
| Add | Adds a new column node to the tree view and resets the fields in the Columns wizard to their initial values. |
After one column is added, you can select Finish. This action constructs a SQL string, executes the code, and commits it. You can edit and save the SQL string by selecting Open script in editor upon completion of wizard on the OpenEdge Schema Editing preferences page.