DB query

DB query (component - data source). Represents a data set, records of which are formed as a result of SQL-query execution. For creation of a data set the relational mode of data access is used. As opposed to a "Table" component the given data set can contain records of several tables of the database. The query is formed to any tables, it is not necessary from a list, definite in Base Administrator.

Properties of a component are the followings: Left, Name, Top.

Active - defines whether the query is activated or not, possible values - True, False. False value is assigned by default. If property has True value the results visualization of query execution in a component, hooked up to a considered data set with a name, definite in Name property is implemented.

Database path - contains a name of the directory, in which one DB tables, or alias of a DB are arranged. Is selected by using the dialogue of choice of the concrete directory or alias of path to a place  where  the DB tables participating in a query are arranged.

Query code (SQL)- contains a query text, on account of which one records are selected into the data set. The query includes commands of the language SQL and is fulfilled at discovery of a data set. At creation of a query the editor for text input of SQL query is called. At creation of a query it is possible to use the Query builder - editor permitting to enter and to execute SQL - queries (the main information about SQL language is given in item 2.6.1. of documentation).

Request live - defines possibility of change of data set returned after execution of SELECT operator. The value of property is set automatically depending on execution of following conditions:

- data set is forming by call only to one physical table of a DB;

- data set is not sorted (i.e. in a query there should not be ORDER BY section);

- in data set there is no value created with the help of aggregate functions: SUM, COUNT, AVG, MIN, MAX.