1. Introduction
A CheckBoxList is used in many ASP.NET WebForms applications to let users choose more than one choice. These choices are frequently kept as comma-separated values in the database.

At first, the system kept text-based frequency values such as:

• Every day
• Every week
• Every month

Later, it became necessary to record numerical codes rather than text values:

• Every day → 1
• Weekly → 2
• Every month → 3

The database already had a lot of entries with the outdated text values, therefore it was necessary to change them into numeric codes without interfering with the functionality that was already in place.

This article describes how to use dummy sample data to deal with this scenario.

2. CheckBoxList Original (Old Input)
The program used to store text data.

Earlier the application stored text values.

<asp:CheckBoxList ID="ckFrequency" runat="server">
    <asp:ListItem Value="Daily">Daily</asp:ListItem>
    <asp:ListItem Value="Weekly">Weekly</asp:ListItem>
    <asp:ListItem Value="Monthly">Monthly</asp:ListItem>
</asp:CheckBoxList>

Example Stored Values

3. Updated CheckBoxList (New Input)

Later, the values were changed to numeric IDs.
<asp:CheckBoxList ID="ckFrequency" runat="server">
    <asp:ListItem Value="1">Daily</asp:ListItem>
    <asp:ListItem Value="2">Weekly</asp:ListItem>
    <asp:ListItem Value="3">Monthly</asp:ListItem>
</asp:CheckBoxList>

New Values Stored in Database

4. Problem
The database already had existing records stored as text values:

But the application now expects numeric values such as:

Without converting existing data, the application might produce incorrect results or filtering errors.

5. Solution: Update Existing Data Using SQL
We can convert the old text values into numeric codes using the SQL REPLACE function.
SQL Script

UPDATE DataFrequency
SET Frequency = REPLACE(Frequency,'Daily','1');

UPDATE DataFrequency
SET Frequency = REPLACE(Frequency,'Weekly','2');

UPDATE DataFrequency
SET Frequency = REPLACE(Frequency,'Monthly','3');

This query replaces the text values in all existing records.

6. Example Result
Before Update

After Update

7. Handling New Selections in ASP.NET
To store selected numeric values from the CheckBoxList, the following C# code can be used:
string freq = "";

for (int i = 0; i < ckFrequency.Items.Count; i++)
{
    if (ckFrequency.Items[i].Selected)
    {
        freq += ckFrequency.Items[i].Value + ",";
    }
}

if (!string.IsNullOrEmpty(freq))
{
    freq = freq.TrimEnd(',');
}

Example
If the user selects:
Daily
Monthly

The stored value will be:
1,3

8. Best Practices

• Store numeric IDs instead of text values in the database
• Always create a backup before running update scripts
• Use IDs for filtering and APIs to improve performance
• Keep display names separate from stored values

9. Backup Before Running Update
Before modifying production data, create a backup table:
SELECT * INTO DataFrequency_Backup
FROM DataFrequency

10. Conclusion
Changing database values from text to numeric IDs improves:

• performance
• consistency
• filtering
• system scalability

By updating existing records using SQL and modifying the CheckBoxList values, applications can continue working smoothly without losing old data.

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