ER/Studio - Embarcadero Technologies Product Documentation

USING ER/STUDIO > DEVELOPING THE LOGICAL MODEL
• Attribute Name: The attribute name is by default the column name. If you want a different column name, type a
new one in the box. ER/Studio uses this name when generating the physical model.
• Default Column Name: The attribute name is by default the column name. If you want a different column name,
type a new one in the box. ER/Studio uses this name when generating the physical model.
• Logical Rolename: This option is only available when there is an overlapping foreign key in a logical model and
the Synchronize Column Rolename with Logical Rolename option is not selected. Use this when the name of the
child attribute differs from the parent attribute. In the logical model, ER/Studio distinguishes between the logical
rolename and the column rolename. ER/Studio uses the column rolename when generating the physical model.
• Hide Key Attribute: If selected, hides the key in the child entity. Commonly used to support partial migration of
PK columns when you do not want to migrate primary key columns into child tables. ER/Studio will not generate a
foreign key because most database systems require that FKs have the same number of columns as the child. By
selecting this option, you will “remove” the column from the child table so that it won’t show up in any child tables
further down the FK chain, in DDL generations or in comparisons to the database. It will display as unavailable
when editing the child table, but you can make it available again later.
• Logical Only: If selected, the entity will not be implemented as a table when generating a physical model, and
will be ignored when comparing the logical model with a physical model.
• Synchronize Column Rolename with Logical Rolename Available when the attribute selected is a foreign key.
This option affects name modification in the entity or table editor, on-screen name editing, and name modification
in the Data Model Explorer. Lets you change the role names of foreign attributes or columns to the same names
as other attributes or columns in the same entity or table. Duplicates will be unified when the user ends the edit
session.
Datatype tab
• Override Bound Data: Overrides datatypes on an attribute basis (for supported types: SQL Server, Sybase, IBM
DB2 for LUW, and IBM DB2 for OS/390). Used to handle any exceptions while maintaining the binding to the
same domain. For example, there is a VARCHAR domain on two separate DBMS platforms. The character
domain’s primary use can be on Oracle. You specified it as VARCHAR (which will be VARCHAR2 in Oracle). Using
this option, you can have a DB2 model where it is implemented it as CHAR. You can customize the domain’s
implementation to accommodate the specific platform, without losing the bindings between DB2 columns and the
domain.
• Identity Properties: For numeric datatypes for which nulls are not allowed and for whose datatype supports
identity properties, you can specify identity properties by selecting the Identity Column option and then specifying
a seed and increment value. The seed and increment values are used to automatically generate sequential
numbers for each row in the table beginning with the Seed value and incrementing by the amount specified by
Increment. The default seed and increment values are one but can be changed.
• Edit LOB Segment: If the specified datatype of the column is BLOB, CLOB, or NCLOB, you can click Edit LOB
Segment option to define LOB storage. For more information, see Oracle LOB Segment Storage Options.
• Character Set: For the Teradata platform, if the specified datatype of the column is CHAR, VARCHAR or CLOB,
you can then specify the character set for the datatype. Click the list to choose the appropriate datatype. For the
CHAR and VARCHAR datatypes, you can choose DEFAULT, LATIN, UNICODE, GRAPHIC, KANJI1, KANJISIS.
The CLOB datatype supports only LATIN and UNICODE character sets.
• CASESPECIFIC: For theTeradata platform, if the specified datatype of the column is CHAR or VARCHAR, you
can choose the CASESPECIFIC option, which indicates the system should differentiate between upper-case and
lower-case characters.
EMBARCADERO TECHNOLOGIES > ER/STUDIO® 8.0.3 USER GUIDE 125