Creating a query in SQL code

1. Click among the quick access buttons.
   • The element creation window appears: click "Query".
   • The query creation wizard starts.
2. Specify that you want to create a query by entering the SQL code directly ("SQL code" option).
3. If your project is linked to no analysis, specify the analysis to which the query will be attached.
   Validate the wizard screen.
4. Type the query name (name of ".WDR" file corresponding to the query). This name will be used to identify the query in your programs.
5. Specify the caption of the query by briefly describing the purpose of query. This caption will be used in the project documentation.
   Remark: The query name is automatically defined from the caption typed.
6. Validate the query creation. A code window is displayed.
7. Type the SQL code of your query. You can insert into the query:
   • comments by writing the "--" or "//" character in front of them. Only comments about the selection conditions will be taken into account during the reverse engineering of the query: the other comments will be automatically deleted. The comments about the selection conditions with parameters will not be proposed when running a GO of query.
   • WLanguage functions. The WLanguage functions must be prefixed by "WL.". Assisted input is available. The WLanguage functions can be nested. Example:
     
     SELECT Customer.CustomerNum FROM Customer
     WHERE WL.LEFT(Customer.ZipCode,2)=75
     
     You cannot run queries whose SQL code contains WLanguage functions.
8. Save the SQL code ( ).

Reverse engineering of query in SQL code

1. Display the SQL code of the query.
2. To represent the query graphically, go to the "Query" pane, "Analyze" group and click "Reverse Engineering".

• This feature is available for the SELECT, UPDATE, DELETE and INSERT queries.
• The sub-queries are not imported.
• The queries of queries are not supported.
• The UNION queries are not supported.
• This feature is available only if the SQL commands used in the query are recognized by the HFSQL engine. See SQL commands available in an SQL query for more details.

• typed in the query editor. Then, the query is run by HExecuteQuery.
• typed in HExecuteSQLQuery in the code editor.

• Running an SQL query while checking the SQL code: This option is available by default for all the SQL queries run from WINDEV. The SQL code of the query must use the commands listed below. In this case, the HFSQL engine checks the SQL code of query.
• Running an SQL query without checking the SQL code (with the hQueryWithoutCorrection constant): This option is recommended for the queries run via a native access or OLE DB. In this case, the HFSQL engine does not check the query. This option must be used if the query contains commands specific to a connection type (Oracle, SQL Server, etc.). All the SQL commands supported by the accessed database can be used.

• for a Select Query: click the "Advanced" button of the description window and check "Run with hQueryWithoutCorrection in test mode" in the "hQueryWithoutCorrection" tab.
• for an Insert query, an Update query or a Delete query: check "Run hQueryWithoutCorrection in Test Mode" in the "General" tab in the description window.