SelectStatement Class

In This Topic

Composes, modifies and parses SELECT statements.

Syntax

Visual Basic
C#

'Declaration
 
Public Class SelectStatement

public class SelectStatement

Remarks

The SelectStatement class is designed for easy manipulation of SQL SELECT statements. It allows you to perform the following tasks:

Construct SELECT statements in run time;
Modify the statements with object-oriented interface;
Parse the statements from strings.

The SelectStatement class exposes SELECT, ORDER BY and GROUP BY clauses as collections of SelectColumn objects (SelectColumnCollection), and FROM clause as collection of SelectTable objects (SelectTableCollection). The WHERE and HAVING clauses are represented as string expressions.

To obtain the statement text use the ToString method.

Instances of this class cannot be created directly. To use its functionality, one needs to create an object of a descendant class, like OracleSelectStatement.

Example

This example illustrates how to construct in run time a SelectStatement object the represents the following query:

SELECT Test.td.dname AS Department,td.loc AS Location,te.ename AS Name 
FROM Test.dept AS td,emp AS te 
GROUP BY te.empno
ORDER BY te.ename

csharp

SelectStatement stmt = (SelectStatement) new OracleSelectStatement();      

stmt.Columns.Add(new SelectColumn("test", "td", "dname", "Department"));
stmt.Columns.Add(new SelectColumn("", "td", "loc", "Location"));
stmt.Columns.Add(new SelectColumn("", "te", "ename", "Name"));

stmt.Tables.Add(new SelectTable("test", "dept", "td"));
stmt.Tables.Add(new SelectTable("", "emp", "te"));

stmt.GroupBy.Add(new SelectColumn("", "te", "empno", ""));

stmt.OrderBy.Add(new SelectColumn("", "te", "ename", ""));

Visual Basic

Dim stmt As SelectStatement = New OracleSelectStatement()

stmt.Columns.Add(New SelectColumn("test", "td", "dname", "Department"))
stmt.Columns.Add(New SelectColumn("", "td", "loc", "Location"))
stmt.Columns.Add(New SelectColumn("", "te", "ename", "Name"))

stmt.Tables.Add(New SelectTable("test", "dept", "td"))
stmt.Tables.Add(New SelectTable("", "emp", "te"))

stmt.GroupBy.Add(New SelectColumn("", "te", "empno", ""))

stmt.OrderBy.Add(New SelectColumn("", "te", "ename", ""))

Inheritance Hierarchy

System.Object
Devart.Common.SelectStatement
Devart.Data.Oracle.OracleSelectStatement

Reference

SelectStatement Members
Devart.Common Namespace

Send Feedback