SQLExec (Function)

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SQL functions

SQLExec

Presentation

Example

Running the query

Retrieving the query result

INSERT query

Managing text memos

Managing binary memos

SQL query (SQLExec or queries created in the query editor)

Comparison with the syntax of HExecuteSQLQuery

SQLExec and threads

Limitations in PHP

See also

SQLExec (Function)

In french: SQLExec

Names and runs an SQL query.

Caution: SQLExec does not start the process for retrieving the result in memory. The result is retrieved during the first call to one of the following functions: SQLFirst, SQLTable or SQLFetch.

Remark: To handle a binary memo in a query, use the WDBinaryMemo keyword in the text of your query (for more details, see remarks).

This function is available when accessing external databases via a Webservice.

The SQL functions are used to handle the local databases (such as Web SQL databases). For more details, see Accessing a database in local mode (SQLite).

Example

See additional examples

// Connect to the database
// (SQLConnect or SQLConnectWS functions)

// Run the query and retrieve the result line by line
i is int = 0
SQLExec("SELECT LASTNAME, FIRSTNAME, EXTENSION, PHOTO FROM CUSTOMER", "QRY1")
WHILE SQLFetch("QRY1") = 0 // There is still another line to read
i++
// Retrieve the data
LASTNAME[i] = SQLGetCol("QRY1", 1)
FIRSTNAME[i] = SQLGetCol("QRY1", 2)
EXTENSION[i] = SQLGetCol("QRY1", 3)
{"IMAGE"+i} = SQLGetMemo("QRY1", 4)
END
SQLClose("QRY1")

// Disconnect (SQLDisconnect)

Syntax

Running an SQL query Hide the details

<Result> = SQLExec(<SQL query text> , <Query name>)

<Result>: Boolean

True if the query was executed,
False otherwise. If the query was not run, the error message can be returned by the SQL.MesError variable once SQLInfo has been run.

<SQL query text>: Character string

SQL code of query to run.

<Query name>: Character string

Name associated with the query text. Corresponds to:
the logical query name.
the name and full path of query (".WDR" file).
The query name corresponds to the logical query name only.

Running an SQL query in browser code Hide the details

<Result> = SQLExec(<SQL query text> , <Query name> [, <WLanguage procedure>])

<Result>: Boolean

True if the query was executed,
False otherwise. The query execution is asynchronous: the function requests the query execution then the current process continues to run without retrieving the query result.
The result of SQLExec can only be used to manage the connection problems. We advise you to check the proper query execution in the <Procedure name> procedure.

<SQL query text>: Character string

SQL code of query to run.

<Query name>: Character string

Name associated with the query text.

<WLanguage procedure>: Procedure name

Name of WLanguage procedure to run during the execution of the SQL query.
This procedure can be a browser procedure global to the project or a browser procedure local to the page that contains the code currently run. This procedure has the following format:

PROCEDURE <Procedure name>(<Query name>)

where <Query name> is the name of query currently run.
This procedure is started at the end of real query execution (regardless of the query result). This browser procedure is used to:
check the proper execution of the query. SQLInfo is automatically run during the call to the procedure. Therefore, all the SQL variables are positioned. If an error occurred, SQL.Error will differ from "00000". The error message is returned by the SQL.MesError variable.
browse the query result.
If new queries are run in this procedure (to add records for example), you can:
use the same procedure: the parameter of this procedure is used to find out the query currently run.
use a different browser procedure to test the result of these new queries.

Remarks

Running the query

The information regarding the query execution is returned by SQLInfo. The SQL.NbCol variable contains the number of columns found in the query result.

Once it was run and processed, the query must be freed by SQLClose.

Retrieving the query result

Then, the query result can be:

Transferred into a table or into a list box (SQLTable).
Transferred into controls or variables (SQLAssociate).
Retrieved line by line (SQLFetch).

INSERT query

When running an INSERT query, the SQL.IDAuto variable contains the automatic identifier that was added during the previous INSERT.

Managing text memos

In the <Query text> parameter, a text memo is used like a text variable. For example:

// Query with condition on a text memo whose value is "Good customer"
QueryText = "SELECT CUSTNAME FROM CUSTOMER WHERE CUSTOMERMEMO = 'Good customer'"
SQLExec(QueryText, "QRY1")

Managing binary memos

To write a binary memo in a table (using an SQL UPDATE or INSERT command), the following syntax must be used in the text of the query:

{WDBinaryMemo('<FileName>' [, 'File'])}

where:
- File (default value) indicates that the memo is a binary memo (coming from a file).
- WDBinaryMemo is a reserved word.
- <FileName> is the physical name of a file.
  Case of access to external databases via a Webservice: The file path corresponds to a path local to the application that runs the Webservice (i.e. a path on the mobile device).
{WDBinaryMemo('<FileName>' [, 'TextFile'])}

where:
- TextFile indicates that the memo is a text memo (coming from a file).
- WDBinaryMemo is a reserved word.
- <FileName> is the physical name of a file.
  Case of access to external databases via a Webservice: The file path corresponds to a path local to the application that runs the Webservice (i.e. a path on the mobile device).

For example:

// Insert the C:\PHOTO\SMITH.BMP file into a binary memo
QueryText = "INSERT INTO CUSTOMER VALUES ('SMITH', 'John'," + ...
"{WDBinaryMemo('C:\PHOTO\SMITH.BMP')})"
SQLExec(QueryText, "QRY1")
// Insert the C:\DOC\LETTER.TXT file into a text memo
QueryText = "INSERT INTO CUSTOMER VALUES ('THOMPSON', 'Christopher'," + ...
"{WDBinaryMemo('C:\DOC\LETTER.TXT', 'TextFile')})"
SQLExec(QueryText, "QRY1")

Remark: Inserting binary memos into an HFSQL file with the SQL functions is not possible and it triggers an error. The error message is as follows: "Unable to initialize the query. Unexpected {WDBinaryMemo( character".

SQL query (SQLExec or queries created in the query editor)

When using the SQL DELETE, INSERT or UPDATE statements, no integrity check and no duplicate check are performed on an HFSQL database. This feature is not available in this version.

Solution: Use the HFSQL functions (HDelete, HAdd or HModify) on your data files. The integrity check and the duplicate check will be automatically performed.

Remark: HExecuteQuery and HExecuteSQLQuery are used to check the integrity and the duplicates on an HFSQL database.

Comparison with the syntax of HExecuteSQLQuery

HExecuteSQLQuery can also be used to run an SQL query. The parameters of these two functions are identical but their order is reversed: HExecuteSQLQuery indicates the name of the query first, then the text of the query (using the same standard as all HFSQL functions).

The syntax of SQLExec is kept for backward compatibility.

SQLExec and threads

When SQLExec is run in a secondary thread, the connection must be established in the same thread: the connection cannot be established in the main thread (project or window). The connection established by SQLConnect is not shared in the other threads.

Limitations in PHP

The binary memos cannot be handled in this version. The query is run on a MySQL database.
The multiple queries are not supported. For example:

DROP TABLE TEST ;
CREATE TABLE TEST (`IDTEST` INTEGER PRIMARY KEY ,
`recipient` VARCHAR(50) NOT NULL ,
`testname` VARCHAR(50) NOT NULL ,`PRODUCTNAME` VARCHAR(50) NOT NULL );

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