Reading -to a Buffer

This tutorial describes how to read the data from the table into a buffer.

Introduction

This query allows you to retrieve -the data in a field. You can retrieve one entry or multiple entries in the -same column by executing the query in a loop.

Basic procedure

The high level steps to read the -data into the buffer are shown here:

Configure the SQL statement.
Allocate memory and -copy data.
Deallocate memory.

Detailed steps

The steps to read data to a buffer -are as follows:

Configure -the SQL statement

Instantiate an RSqlStatement object -and declare the variables as required.

RSqlStatement myStatement; -TInt err;

Allocate -memory and copy data

To retrieve all the entries, use a loop. -The steps to be performed within the loop are as described below:

Instantiate an object -of the RBuf class.
while((err = myStatement.Next()) == KSqlAtRow) - { - RBuf myBuffer;
Allocate enough memory -to hold the column data using the CreateL() function as shown -below.
err = myBuffer.CreateL(myStatement.ColumnSize(columnIndex));
Copy the data from the -table into the buffer using ColumnBinary() function.
err = myStatement.ColumnBinary(myColumnIndex,myBuffer); - ... - // process data

Deallocate -memory

Deallocate the memory assigned to the RBuf object.

myBuffer.Close(); - }

See also

Querying -a Database

Deleting -Rows from a Table

Reading to a buffer - This document

Reading to Memory

Reading to a Data Stream

Writing to a Data Stream

Performing Scalar Queries

+ + + + + +Reading +to a Buffer +

This tutorial describes how to read the data from the table into a buffer.

Introduction

This +query allows you to retrieve the data in a field. You can retrieve one entry +or multiple entries in the same column by executing the query in a loop.

Basic procedure

The +high level steps to read the data into the buffer are shown here:

Configure the SQL statement.
Allocate memory and +copy data.
Deallocate memory.

Detailed steps

The +steps to read data to a buffer are as follows:

Configure +the SQL statement

Instantiate an RSqlStatement object +and declare the variables as required.

RSqlStatement myStatement; +TInt err;

Allocate +memory and copy data

To retrieve all the entries, use a loop. +The steps to be performed within the loop are as described below:

Instantiate an object +of the RBuf class.
while((err = myStatement.Next()) == KSqlAtRow) + { + RBuf myBuffer;
Allocate enough memory +to hold the column data using the CreateL() function as shown +below.
err = myBuffer.CreateL(myStatement.ColumnSize(columnIndex));
Copy the data from the +table into the buffer using RSqlStatement::ColumnBinary(TInt,TDes8 +&)const function.
err = myStatement.ColumnBinary(myColumnIndex,myBuffer); + ... + // process data

Deallocate +memory

Deallocate the memory assigned to the RBuf object.

myBuffer.Close(); + }