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Visio FAQ: Ordering columns in index creation |
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Visio FAQ
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By Scot Becker on
10/22/2004
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In some DBMS’s, the order in which columns appear in the creation/definition of an index (which spans multiple columns) can have performance impacts. Should you be saddled with such a silly restriction, you might be wondering how to specify the column order within Visio.
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N-ary fact verbalizations |
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Visio Tool Tips
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By Scot Becker on
10/20/2004
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For any given fact type, there are n! (read: n factorial) readings of that fact type (where n is the number of roles in the fact type). In a unary fact type, there is exactly one reading, in a binary there are two readings, in a ternary there are six readings (3 x 2 x 1), in a quaternary there are 24 readings (4 x 3 x 2 x 1), and so on.
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Using Namespaces in ORM Source Models |
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Visio Tool Tips
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By Scot Becker on
10/14/2004
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Many object types have similar (usually, descriptive) properties. For example, People, Animals, Products, and so on, all have names. This poses a choice for the ORM Modeler: do you create one "Name" object type or multiple?
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Cloning and Reusing Model Elements in Visio |
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Visio Tool Tips
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By Scot Becker on
10/12/2004
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Although Visio supports the standard cut-copy-paste operations found in most software, the results might not be what you expect because Visio separates the notion of the definition of a model element (e.g. a table, object type, predicate, whatever) from the shape(s) used to display that element.
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Visio Bugs |
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Site Announcements
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By Scot Becker on
10/7/2004
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I’ll be adding a new section shortly to catalog bugs related to the database functionality (ORM Source, ER Source, and Database Model Diagrams) in Visio for Enterprise Architects.
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Verbalization of Reference Modes |
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Visio Tool Tips
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By Scot Becker on
10/7/2004
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On the "Ref Mode" tab of the "Database Properties" sheet for an object type, you may have noticed the "Type" drop down list. This list is enabled if the selected object type is an entity type and has a simple (internal) reference mode.
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External Frequency Constraints |
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ORM Primers
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By Scot Becker on
9/27/2004
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Just as internal uniqueness constraints can be generalized to internal frequency constraints, external uniqueness constraints can be generalized to external frequency constraints.
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Frequency constraints |
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ORM Primers
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By Scot Becker on
7/30/2004
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Adding a frequency constraint to a role means that once the role is populated with a given object instance, that same object instance must populate the role between some minimum and some maximum number of times.
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Visio FAQ: Creating set constraints in VEA |
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Visio FAQ
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By Scot Becker on
7/28/2004
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The Visio for Enterprise Architects (VEA) constraint editor can be a little confusing when it comes to creating set (subtype, equality, and exclusion) constraints. I’ll describe how to create these constraints using examples from a related entry.
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