Glossary

`::=`		In descriptions of the PQL language, this symbol is shorthand for "is equivalent to" or "can be made of." For example, the phrase `assignment ::= path = expression \| path = tree_literal` means that an assignment can be made of a path, and the path can be an expression or a tree literal.
absolute path		The definition of a node by the branches to it, starting from the root of the tree. For example, the absolute path of an interface in the sample database is `/network/device/interface`.
anchor-point node		The node closest to the root in the clause of a PQL statement.
application		A program or plugin that extends Paglo's capabilities, such as the Paglo Alerts and Paglo Inventory.
argument		A value that is passed to a function, such as X in child(X). In PQL, argument is synonymous with parameter.
assignment		A path, an expression and path, or a tree_literal.
assignment_list		A list of one or more assignments..
application provider		A person or company that develops a program or plugin that extends Paglo's capabilities via the Paglo API. We here at Paglo create such applications, and we encourage you to try your hand at it, too.
API		The Paglo API enables applications to be incorporated directly into Paglo, dramatically extending its value. After you load an application, it uses information in the Search Index to add specific functionality. Some applications are developed here at Paglo (such as the Network Map), and others are created by independent third parties that are part of our growing community.
boolean expression		An element of Paglo's PQL language that results in a Boolean value (true or false), such as: `WHERE ../interface/name = 'eth0'`.
conditional tree assignment		An element of Paglo's PQL language that represents a tree_assignment by defining it with conditions, such as `interface[name='eth0']`.
conditional tree literal		An element of Paglo's PQL language that represents a tree_literal by defining it with conditions, such as `interface[name='eth0']`. A conditional_tree_literal is one or more conditional_tree_assignments.
Crawler		The Paglo Open Source Crawler is an agent or spider that gathers information throughout your IT network, and securely sends the information to the Paglo Search Index. Install it on just one computer or server to probe your entire network.
dual database		The unique architecture of the Search Index that stores data in two forms: unstructured and structured.
expression		A set of instructions that when executed return a value. Use expressions with operators to operate on constants, paths, or the results of functions.
mashup		To combine data or capabilities from different sources in a plugin or web application in a way that benefits all. In particular, an application or plugin that extends Paglo's capabilities.
parameter		A value that is passed to a function, such as X in child(X). In PQL, parameter is synonymous with argument.
path		The location of the anchor-point node in a tree, such as `a`, `a/b`, `a/b/c`, and so on. But not `a/`, because a trailing slash is meaningless in PQL.
path-scoped predicate		A predicate (`WHERE` clause) that is limited by a path, such as: `WHERE interface/(name = 'eth0' and ip_address = '1.2.3.4')`
path-scoped projection		A projection (`SELECT` clause) that is limited by a path, such as: `SELECT /network/device/interface/(name = 'dell' and ip_address = '5.5.5.5')`
Platform		The Paglo Platform is the collection of systems and software that comprise the service. It is what the Paglo API provides open access to, so third parties can develop applications that provide additional value to members.
PQL		PQL, or the Paglo Query Language, is the SQL-like query language developed to interact with Paglo's tree-structured database.
pql_statement		A statement that conforms to the requirements of the Paglo Query Language.
predicate		The part of a PQL statement that returns a Boolean value, such as `WHERE interface/name = 'eth0'`.
projection		The `SELECT` clause of a PQL statement that starts a query, such as `SELECT * FROM /`. This example asks for all information at the level of the root node.
qualified path		A path that is restricted with the [ ] operator, such as: `interface[name = 'eth0']/ip_address`
relative path		The partial definition of a node by the branches to it, not starting from the root of the tree. For example, the relative path of an interface in the sample database might be `device/interface`.
restriction		The `WHERE` clause; the part of a PQL statement that further specifies the node defined in the `FROM` clause.
Search Index		The Paglo Search Index is the repository that stores the information that the Paglo Crawler gathers about your network and IT assets. You can query the complex IT information stored in the Search Index, and get results in rich table and chart formats, as well as the familiar simple text hit lists that other search engines provide.
select column		A PQL expression that indicates which data to select.
select column list		The select_column_list expression indicates which data to select, and returns zero or more columns of data. For example, if you use , as in `SELECT FROM /network/device`, then all trees and all sub-trees from the `/network/device` anchor-point are returned in the query results.
simple path		One way to represent the anchor-point node. A simple_path is always an absolute path, starting with a slash to represent the root node, and using slashes to separate each subsequent node, if there are any. An example of a simple_path that limits the query to the contents of device nodes would be: /network/device.
sort expression		An expression that sorts the results of a query.
sort expression list		A list of sort_expressions.
tree		A data structure of nodes attached in parent-child relationships, that represent the hierarchical and relational structure of the data. Each node is attached to only one parent, but can have one or more child nodes directly beneath. The one exception is the root at the very top of the tree, which has no parent. Because the root is at the top, it is sometimes called an inverted tree structure. The connection between any two nodes is a branch. The nodes at the end of each branch are leaves or leaf nodes. Only leaf nodes contain values. The elements of a tree include tree_literal, conditional_tree_literal, tree_assignment, and conditional_tree_assignment.
tree_assignment		An element of Paglo's PQL language that represents an identifier as either an expression or a tree_literal.
tree_literal		An element of Paglo's PQL language that represents a tree by defining each branch. For example, a path such as `/network/device` is a tree_literal of three branches: root, network, and device.
tree-structured database		The part of the Search Index where data is stored in structured format, and can be probed by using queries in Paglo's PQL language.
unqualified path		A path that is not restricted with the [ ] operator, such as: `interface/ip_address`
unstructured database		Where data in the Search Index is stored in unstructured format, and can be searched using simple words or phrases in plain English.
Web account		Your Paglo Web Account is the face of Paglo, where you can retrieve the information stored in the Search Index. You can get your IT information by typing in queries or using searches that are shared by others in the Paglo community, which returns the simple text hit lists that we're all familiar with. Keep your finger on the pulse of IT via the customizable Paglo Dashboard page by running queries that return rich data reports in table and chart formats.

How do I find out more?

Learn more about Paglo