(r5) XeoPrimerXeoQL < WebXEO

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-- Main.PedroRio - 27 Dec 2010
---+ XeoQL - XEO Query Language ( also known as BOQL )

XEO Query Language (XEOQL a.k.a BOQL - Business Object Query Language) is a language designed to query instances of XEO Object Models. It's very similar to SQL and has many of the same constructors. SQL is designed to return records from a relational database, while XEOQL is designed to return Object Model instances from its datasource (tipically a relational database).

Using XEO's Java API to issue a XEOQL expression against the datasource will produce a [[XeoPrimerJavaAPIBoObjectList][boObjectList]] instance which can be used to iterate through all elements that are the result of the query. The methods available in [[XeoPrimerJavaAPIObjectListManager][ObjectListManager]] allow you to create a boObjectList instance from a XEOQL query.The syntax for a XEOQL expression is the following:

SELECT [MY] [USING user/pwd] [attlist FROM] objname [WHERE whereStatement (AND | OR whereStament)* ]

Although the syntax may seem complicated usually you'll not use every option in the syntax. Let's start with the simplest of queries, selecting all instances of a given Object Model, for example the system Object Model <em>Ebo_Perf </em>(which represents a user).
<verbatim>select Ebo_Perf</verbatim>

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---+++ Special Constants

There are a number of special constants which can be used when creating a XEOQL expression.The following table summarizes them.
| *Constant* | *Description* |
| CTX_PERFORMER_BOUI | The boui of the user which is executing the query |
| | |
| | |

Table XEOQL.1 - Special constants in XEOQL

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Attachments

Topic attachments
I	Attachment	Action	Size	Date	Who	Comment
png	XEOQL-Console.png	manage	13.4 K	2011-01-04 - 17:52	PedroRio	XEOQL Console - Simple Query

Topic revision: r5 - 2011-01-04 - PedroRio

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