Introduction
Dynamic table generation is a common requirement in SAPUI5 applications. One scenario that I recently worked on involved displaying a few business attributes as fixed columns while generating additional columns dynamically based on data returned from the backend.
For example, in a supplier comparison application, some columns remain fixed:
MaterialDescriptionPlant
The remaining columns are generated dynamically depending on the number of suppliers received from the backend.
While implementing this requirement, I came across an issue that many SAPUI5 developers may have already faced — duplicate ID errors during table refreshes, especially when using createId() while recreating dynamic columns.
In this blog, I would like to share my observations, the root cause of the issue, and an approach that helped me handle dynamic columns in a cleaner and more maintainable way.
Picture 1: Understanding of Duplicate ID Error
Typical Implementation
The table structure consists of two parts as follows:
Fixed Columns (XML View)
<!– Fixed Columns (XML View) –>
<Table id=”supplierTable”>
<columns>
<Column>
<Text text=”Material”/>
</Column>
<Column>
<Text text=”Description”/>
</Column>
</columns>
</Table>
Dynamic Columns (Controller – Js File)
// Dynamic Columns (Controller)
aSuppliers.forEach(function(oSupplier) {
oTable.addColumn(
new sap.m.Column(
this.createId(“supplierColumn”),
{
header: new sap.m.Text({
text: oSupplier.Name
})
}
)
);
}.bind(this));
During the initial load, everything works as expected.
However, when the table is refreshed due to subsequent operations—such as an item-level POST operation, rebinding after user selections, or reloading data based on changed business conditions—the application may throw an error indicating that a control with the same ID already exists.
At first glance, it is easy to assume that createId() is the reason behind the issue.
Understanding the Root Cause
Initially, I thought createId() was generating duplicate IDs. However, after debugging the application flow, I realized that createId() was actually doing exactly what it was supposed to do.
this.createId(“supplierColumn”);
This consistently generates a view-scoped ID such as: MyView–supplierColumn
The real problem is not ID generation.
The actual issue occurs because the previously generated dynamic column is still present in the control hierarchy when the application attempts to create the same column again.
In other words, the issue is related to: Control Lifecycle Management rather than ID Generation
This understanding completely changed the way I approached the solution.
Can an isDynamic Flag Help?
While exploring different implementations, I noticed that many projects introduce a property such as:
isDynamic : true
The purpose of this flag is to identify tables whose structure is generated dynamically at runtime.
Before rebuilding the table structure, logic similar to the following can be executed:
if (this.isDynamic) {
// cleanup logic
}
From my perspective, the important thing to understand is that the flag itself does not solve duplicate ID issues.
What actually resolves the issue is the cleanup operation that runs before recreating the controls.
The isDynamic flag simply acts as an indicator that the table structure needs to be refreshed.
Therefore, its value lies in controlling the rebuild process rather than preventing duplicate IDs directly.
Why destroyColumns() Is Not Always the Best Choice
One straightforward solution is:
oTable.destroyColumns();
This certainly removes the duplicate ID issue.
However, there is a drawback.
If the table contains both fixed columns defined in XML and dynamic columns created in JavaScript, destroyColumns() removes everything.
As a result, even the static columns must be recreated, which may not be necessary.
For smaller applications this may be acceptable, but for larger enterprise applications it introduces additional processing and maintenance effort.
Recommended Approach (How I sorted this issue)
The approach that made the most sense to me was to manage only the dynamically generated columns.
Picture 2: Recommended Approach
Step 1: Store References to Dynamic Columns
this._aDynamicColumns = [];
Step 2: Create Dynamic Columns
var oColumn = new sap.m.Column({
header: new sap.m.Text({
text: oSupplier.Name
})
});
oTable.addColumn(oColumn);
this._aDynamicColumns.push(oColumn);
Step 3: Cleanup Before Refresh
this._aDynamicColumns.forEach(function(oColumn) {
oTable.removeColumn(oColumn);
oColumn.destroy();
});
this._aDynamicColumns = [];
Step 4: Rebuild Dynamic Columns
Once the cleanup is completed, the latest supplier columns can be recreated based on the newest backend response.
This ensures that the fixed XML-defined columns remain untouched while only the dynamic portion of the table is regenerated.
Benefits of This Approach
I found several advantages with this implementation:
Prevents duplicate ID errorsPreserves XML-defined static columnsAvoids unnecessary recreation of controlsImproves maintainabilityKeeps a clear separation between static and dynamic contentMakes future enhancements and debugging easier
Picture 3: Benefits of current approach
Conclusion
While working on dynamic table generation in SAPUI5, I initially assumed that createId() was responsible for duplicate ID errors. After investigating the issue, I realized that the real challenge was managing the lifecycle of dynamically created controls.
Using an isDynamic flag can be helpful for identifying when a table structure needs to be rebuilt, but it should not be viewed as the actual solution. The key is ensuring that previously generated dynamic controls are properly removed or destroyed before creating new ones.
For applications that combine fixed XML columns with runtime-generated columns, tracking and cleaning up only the dynamic columns is, in my opinion, one of the most practical and maintainable approaches.
If you have any alternative effective solutions, please feel free to share your thoughts and so everyone can learn from each other.
Thank you for taking the time to read this blog! If you found this helpful, i would love to hear your thoughts, feedback or questions in the comments. Let’s keep learning and growing together!
I’m still new to blogging, so if you notice anything that could be improved or corrected, please don’t hesitate to let me know!!
IntroductionDynamic table generation is a common requirement in SAPUI5 applications. One scenario that I recently worked on involved displaying a few business attributes as fixed columns while generating additional columns dynamically based on data returned from the backend.For example, in a supplier comparison application, some columns remain fixed:MaterialDescriptionPlantThe remaining columns are generated dynamically depending on the number of suppliers received from the backend.While implementing this requirement, I came across an issue that many SAPUI5 developers may have already faced — duplicate ID errors during table refreshes, especially when using createId() while recreating dynamic columns.In this blog, I would like to share my observations, the root cause of the issue, and an approach that helped me handle dynamic columns in a cleaner and more maintainable way.Picture 1: Understanding of Duplicate ID Error Typical ImplementationThe table structure consists of two parts as follows:Fixed Columns (XML View)<!– Fixed Columns (XML View) –>
<Table id=”supplierTable”>
<columns>
<Column>
<Text text=”Material”/>
</Column>
<Column>
<Text text=”Description”/>
</Column>
</columns>
</Table> Dynamic Columns (Controller – Js File)// Dynamic Columns (Controller)
aSuppliers.forEach(function(oSupplier) {
oTable.addColumn(
new sap.m.Column(
this.createId(“supplierColumn”),
{
header: new sap.m.Text({
text: oSupplier.Name
})
}
)
);
}.bind(this));During the initial load, everything works as expected.However, when the table is refreshed due to subsequent operations—such as an item-level POST operation, rebinding after user selections, or reloading data based on changed business conditions—the application may throw an error indicating that a control with the same ID already exists.At first glance, it is easy to assume that createId() is the reason behind the issue. Understanding the Root CauseInitially, I thought createId() was generating duplicate IDs. However, after debugging the application flow, I realized that createId() was actually doing exactly what it was supposed to do.this.createId(“supplierColumn”);This consistently generates a view-scoped ID such as: MyView–supplierColumnThe real problem is not ID generation.The actual issue occurs because the previously generated dynamic column is still present in the control hierarchy when the application attempts to create the same column again.In other words, the issue is related to: Control Lifecycle Management rather than ID GenerationThis understanding completely changed the way I approached the solution. Can an isDynamic Flag Help?While exploring different implementations, I noticed that many projects introduce a property such as:isDynamic : trueThe purpose of this flag is to identify tables whose structure is generated dynamically at runtime.Before rebuilding the table structure, logic similar to the following can be executed:if (this.isDynamic) {
// cleanup logic
}From my perspective, the important thing to understand is that the flag itself does not solve duplicate ID issues.What actually resolves the issue is the cleanup operation that runs before recreating the controls.The isDynamic flag simply acts as an indicator that the table structure needs to be refreshed.Therefore, its value lies in controlling the rebuild process rather than preventing duplicate IDs directly. Why destroyColumns() Is Not Always the Best ChoiceOne straightforward solution is:oTable.destroyColumns();This certainly removes the duplicate ID issue.However, there is a drawback.If the table contains both fixed columns defined in XML and dynamic columns created in JavaScript, destroyColumns() removes everything.As a result, even the static columns must be recreated, which may not be necessary.For smaller applications this may be acceptable, but for larger enterprise applications it introduces additional processing and maintenance effort. Recommended Approach (How I sorted this issue)The approach that made the most sense to me was to manage only the dynamically generated columns. Picture 2: Recommended ApproachStep 1: Store References to Dynamic Columnsthis._aDynamicColumns = [];Step 2: Create Dynamic Columnsvar oColumn = new sap.m.Column({
header: new sap.m.Text({
text: oSupplier.Name
})
});
oTable.addColumn(oColumn);
this._aDynamicColumns.push(oColumn);Step 3: Cleanup Before Refreshthis._aDynamicColumns.forEach(function(oColumn) {
oTable.removeColumn(oColumn);
oColumn.destroy();
});
this._aDynamicColumns = [];Step 4: Rebuild Dynamic ColumnsOnce the cleanup is completed, the latest supplier columns can be recreated based on the newest backend response.This ensures that the fixed XML-defined columns remain untouched while only the dynamic portion of the table is regenerated. Benefits of This ApproachI found several advantages with this implementation:Prevents duplicate ID errorsPreserves XML-defined static columnsAvoids unnecessary recreation of controlsImproves maintainabilityKeeps a clear separation between static and dynamic contentMakes future enhancements and debugging easier Picture 3: Benefits of current approach ConclusionWhile working on dynamic table generation in SAPUI5, I initially assumed that createId() was responsible for duplicate ID errors. After investigating the issue, I realized that the real challenge was managing the lifecycle of dynamically created controls.Using an isDynamic flag can be helpful for identifying when a table structure needs to be rebuilt, but it should not be viewed as the actual solution. The key is ensuring that previously generated dynamic controls are properly removed or destroyed before creating new ones.For applications that combine fixed XML columns with runtime-generated columns, tracking and cleaning up only the dynamic columns is, in my opinion, one of the most practical and maintainable approaches.If you have any alternative effective solutions, please feel free to share your thoughts and so everyone can learn from each other.Thank you for taking the time to read this blog! If you found this helpful, i would love to hear your thoughts, feedback or questions in the comments. Let’s keep learning and growing together!I’m still new to blogging, so if you notice anything that could be improved or corrected, please don’t hesitate to let me know!! Read More Technology Blog Posts by Members articles
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