Schema roots

All of us have some notion of what schema means because we have encountered the term in a number of well-known places. 

Two central meanings predominate in Plato s dialogues. First, schema (translated variously as form, shape, figure, or fashion ) often occurs, along with color, sound, or music, 3 in discussions about the intrinsic nature of objects for example, in the case of letters, we both see and know the form [schema] and color. 4 A second use occurs with abstract concepts, as in the form [schema] of a law, 5 the shapes [schemas] of lives, 6 or the fashion [schema] of a legend. 7 In both contexts, schema indicates the essential commonality of a broad category. 

A large part of the dialogue of Plato s The Meno is a discussion of what is meant by oxT)pa. The highly respected translation of W. R. M. Lamb renders o%r pa as figure in this context. Socrates 

Both Plato and Aristotle wrote a great deal about the a/ripa, and, as noted, it has routinely been translated as form. Thus, we find Aristotle discussing essential forms and Plato describing ideal forms. In fact, they are talking about schematos (or o%T j.aToa, as the plural is written in Greek).13 

Clearly, schema was an important term in the works of Plato and Aristotle, although the two disagreed on several fundamental points. The underlying meaning for both of them seems to be that 

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The core of the language consists of a set of data containers, or more formally elements (not to be confused with the chemical elements), the enumeration of which is ideally defined by a schema. In this example, the elements are , , , , , and . These have a clearly defined relationship to one another (illustrated above by indentation of the text). Thus the element is said to be the parent of a child element termed , and both are children of the top-level element , which can also be called the document root element. This hierarchy among elements is precisely defined and must carry no ambiguity. 

There are many medical conditions for which a root cause is unknown and one has to focus on treating peripheral manifestations (e.g., treating inflammation in arthritis with antiinflammatory drugs). Even when a root cause is known, it may be difficult to treat if the problem is localized to a particular area of the body the medication may not only affect the problem area ir. the body but have side effects on other regions—for example, the side effects of antitumor agents on normal cells. When the toot cause is outside the body, e.g., smoking as a cause of lung cancer, elimination of the root cause can be both feasible and clinically effective. Hence, the importance of Preventive Medicine as an important influence on the hierarchical schema. 

Chapter 1 looks at the history and meaning of the term schema. It summarizes how schemas have been defined and described, beginning with ancient Greek philosophy and closing with modern cognitive science. Most striking is the extent of our debt to the ancient Greeks. Many of our current debates have roots in their philosophical discussions. 

On the other hand, the same problem may present itself over and over again. It still must be solved, but the solution is routine. Herein, one surmises, lies the root of habit. Whenever this particular problem occurs, invocation of the appropriate schema is automatic and requires little conscious thought. If anything untoward occurs during the application of the schema, more attention is directed to the problem, and the processing may become controlled rather than automatic. 

Schema theory has existed in one form or another for a long time. It has been tremendously important in Western culture, with roots as deep as any other psychological phenomenon. To be sure, at different times in history, theorists have focused on different...

The root of that graph schema is the node class ModelElement which carries common attributes for all modeling concepts like a name. This basic node class is specialized on the next inheritance level into the node class Entity and the node class Relationship (cf. part (a) of Fig. 5.60). 

Note that when specifying a schema for an XML column or document, one must also specify a single global element that must serve as the document root for each document instance. In the example above, schema temp. xsd has a global element Global 1 against which all document roots must validate. 

Microsoft SQL Server, like Oracle, supports storing a collection of homogeneous XML documents in a relation column (Pal et al. 2006). Whereas instances in an XML-typed column or table in Oracle must conform to a specific schema with a specific global element as root, an XML-typed column in SQL Server validates against any schema in a collection of schemas and allows any global element as root. One specifies an XML Schema Collection in SQL server using a DDL statement CREATE XML SCHEMA COLLECTION [ . ] sql.identifier AS Expression... 

Structurality. The structurality has been introduced [Duchateau 2009] to intuitively measure the qualities of the structure an object possesses.6 In the case of schemas, this notion is translated to the set of ancestors of a schema structure. In other words, the structurality measures whether the elements of the generated and the intended schema contain the same set of ancestors. To compute structurality, the schemas are viewed as trees. Let S r and Sgen denote the intended and the generated target schema, respectively. Assume also that in the tree representation of a schema S, Ps (e) is the set of elements in the path from the root to the element e, exclusively. The structurality of an element e is defined as follows ... 

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