Query

Synopsis

Query selects data from a table in the current database based on user specifications and returns it to the user.

Input Ports

dbvisual_connect structure

Parameters

None

Output Ports

num_columns int

column_array[] DBcolumn group

Graph1 link

Graph2 link

Graph3 link

Graph4 link

Graph5 link

User Interface

Description

The Query macro selects data from a table or view in the current database based on user specifications in a SQL SELECT statement and returns the data as an array of columns, one for each column specified by the SELECT statement. It provides a user interface to the DBquery module that performs the query and additional modules that perform some support functions. The interface also provides access to additional UIwindows.

Input

dbvisual_connect_descriptor

A pointer to the connection descriptor of the session in which Query is to execute. This is the output of the DBconnect module or Connect macro that initiated the session.

CAUTION: Do not modify this value. A fatal error will result.

Parameters

none.

Output Port

num_columns

A return value that indicates the number of columns in the data rows returned by the query.

column_array[]

The data returned by a SELECT statement. Each element in this array is a DBcolumn group that consists of an array containing a column of returned data, an integer value that indicates whether null data values are present, the value that is to be used to represent a null data value, and the name of the column.

Graph1, Graph2, Graph3, Graph4, Graph5

Links to the Graph tools in the Query interface.

These ports are typically connected to other UIwindows; for example, Viewer3D. When the user selects the corresponding tool from the Query toolbar (see The Toolkits Book ), the selected UIwindow is opened.

Example

Not available.

File

v/db.v

See also related modules