Understanding Report Builder, Report Services, and Dynamic SQL: Mastering Dynamic SQL in Reporting Services

Understanding Report Builder, Report Services, and Dynamic SQL

Introduction

This article aims to delve into the world of Microsoft Reporting Services (RS) and its integration with Reporting Services Web Parts. We’ll explore a specific issue involving dynamic SQL, parameters, and data display between Report Builder 3.0 and Report Services on the web.

Background

Microsoft Reporting Services is a server-based reporting platform that enables users to create, manage, and deploy reports. It consists of several components, including the Reporting Services Web Server (RSS), which acts as an entry point for accessing reports via the web or through other client applications like Report Builder 3.0.

Report Builder 3.0 is a client-side tool used to design, build, and manage reports in RS. When creating a report in Report Builder, developers often use dynamic SQL to fetch data from various databases based on user input parameters.

Key Concepts: Dynamic SQL and Parameters

Dynamic SQL is a technique used in programming where the SQL command or code is generated at runtime instead of being hard-coded into the program. This approach allows for greater flexibility when working with user-defined parameters, as it can dynamically adjust the SQL query to accommodate changing inputs.

In this specific case, we have three parameters: var1, var2, and var3. These parameters are used in conjunction with dynamic SQL to fetch data from multiple datasets (DataSet1, DataSet2, and DataSet3).

Dynamic SQL Example

{
<highlight language="sql">sql</highlight>
    DECLARE @tmpSqlRefTable AS TABLE
    (
        sqlRef1 varchar(50),
        sqlRef2 varchar(50),
        SQLServer varchar(50),
        DB varchar(50)
    )

    INSERT INTO @tmpSqlRefTable
    SELECT l.sqlRef1,
        l.sqlRef2,
        l.SQLServer,
        l.DB
    FROM SqlRefTable l
    WHERE l.sqlRef2 NOT IN ('Location1', 'Location2')

    CREATE TABLE #tmpTable1
    (
        Field1 varchar(100)
    )

    DECLARE sqlCursor CURSOR FOR
    SELECT l.sqlRef1,
        l.sqlRef2,
        l.SQLServer,
        l.DB
    FROM @tmpSqlRefTable l

    OPEN sqlCursor

    DECLARE @sqlRef1 varchar(50),
        @sqlRef2 varchar(50),
        @srv varchar(50),
        @db varchar(50),
        @sqlStr varchar(max)

    FETCH NEXT FROM sqlCursor INTO @sqlRef1, @sqlRef2, @srv, @db

    WHILE @@FETCH_STATUS = 0
    BEGIN
        SET @sqlStr = 
        '
            SELECT DISTINCT LTRIM(trf.Field1) Field1
            FROM [' + @srv + '].[' + @db + '].dbo.Table1 trf
            WHERE trf.Field1 IS NOT NULL
        '

        IF DB_NAME() &lt;&gt; @db
        BEGIN
            SET @sqlStr = 'EXEC(''' + Replace(@sqlStr, '''', '''''') + ''') at ' + @srv;
        END

        INSERT INTO #tmpTable1
        EXEC(@sqlStr)

        FETCH NEXT FROM sqlCursor INTO @sqlRef1, @sqlRef2, @srv, @db
    END

    CLOSE sqlCursor
    DEALLOCATE sqlCursor

    SELECT NULL AS Field1, 'All' As Field1Descrip
    UNION ALL
    SELECT DISTINCT tt.Field1, tt.Field1 AS Field1Descrip
    FROM #tmpTable1 tt

    DROP TABLE #tmpTable1
}
</highlight>

In this example, dynamic SQL is used to fetch data from a database table (Table1) based on the value of @var1. The CASE statement checks for null values in @var1, allowing both true and false values.

The Issue

When viewing the report through Report Builder 3.0’s “Run” command, all the data is displayed as expected. However, when attempting to view the same data through Report Services on the web using the same parameters (var1, var2, and var3), none of the reports display (not even the title).

Possible Causes

Given the provided dynamic SQL code, there are a few potential causes that might be contributing to this issue:

Incorrect or missing connection: Ensure that the connections to the databases (DataSet1, DataSet2, and DataSet3) are correctly established in Report Services.
Insufficient permissions: Verify that the user account used by Report Services has sufficient permissions to access the required data sources.

Solution

To resolve this issue, it’s essential to understand how dynamic SQL works within Report Services. While the provided code snippet uses a client-side tool (Report Builder 3.0) to generate and execute dynamic SQL, similar logic is applied in the server-side context of Report Services.

Adapting Dynamic SQL for Report Services

To achieve a successful data display through Report Services, you need to adapt your approach to utilize report-specific parameters (@var1, @var2, @var3) within the report’s dynamic SQL.

Here is an example using C# code-behind:

{
<highlight language="c#">csharp</highlight>
using System;
using System.Data;

// Declare variables for input parameters
string var1Value = ReportParameters["Var1"].ToString();
string var2Value = ReportParameters["Var2"].ToString();
string var3Value = ReportParameters["Var3"].ToString();

// Create the SQL query with report-specific parameter values
string sqlQuery = @"
    SELECT DISTINCT 
        Field1,
        CASE 
            WHEN Field1 IS NULL THEN 'No'
            ELSE 'Yes'
        END AS IsFieldNull
    FROM 
        #ResultsTable
    WHERE (@var2 IS NULL OR Field2 = @var2Value)
        AND 
        (CASE 
            WHEN @var1Value IS NULL AND Field1Field != 1 THEN 1
            WHEN @var1Value = 1 AND Field1Field = 1 THEN 1
            WHEN @var1Value = 0 AND Field1Field = 0 THEN 1
        END) = 1";

// Open a connection to the report database
using (SqlConnection connection = new SqlConnection("Your Connection String Here"))
{
    connection.Open();

    // Create a command object for executing the SQL query
    SqlCommand command = new SqlCommand(sqlQuery, connection);

    // Add parameters to the command
    command.Parameters.AddWithValue("@var2Value", var2Value);
    command.Parameters.AddWithValue("@var1Value", var1Value);

    // Execute the SQL query and fetch results
    DataTable dataTable = new DataTable();
    SqlDataAdapter adapter = new SqlDataAdapter(command);
    adapter.Fill(dataTable);

    // Display the fetched data in the report
    foreach (DataRow row in dataTable.Rows)
    {
        ReportItems.AddNewRow(row.ItemArray);
    }
}
</highlight>

In this example, report-specific parameters (@var1, @var2, and @var3) are utilized within the dynamic SQL query. This approach allows for a more seamless integration of user input values into the report’s data display.

Conclusion

To resolve issues involving dynamic SQL in Report Services, it is crucial to understand how report-specific parameters can be effectively integrated into the code-behind logic. By adapting your approach to utilize these parameters within the dynamic SQL query, you can achieve a successful data display through Report Services.

In this article, we explored the complexities of working with dynamic SQL in Report Builder 3.0 and Report Services on the web. We delved into key concepts like connection establishment, parameter handling, and report-specific logic. By applying these insights to your own reporting needs, you can create more robust and user-friendly reports that seamlessly integrate data displays based on dynamic input values.

Additional Resources:

By staying up-to-date with the latest reporting technologies and best practices, you can ensure that your reports are effective, efficient, and user-friendly. Happy building!

Last modified on 2024-05-24