# excel_table - Server Quirks
**Data Model workflow (CRITICAL)**:
Excel Tables on worksheets are NOT automatically in the Data Model (Power Pivot).
To analyze worksheet data with DAX measures:
1. Ensure data is formatted as an Excel Table (use create action if needed)
2. Use `add-to-datamodel` action to add the table to Power Pivot
3. Then use `excel_datamodel` to create DAX measures on it
**Action disambiguation**:
- create: Create NEW table from a range (requires sheetName, tableName, rangeAddress)
- read: Get table metadata (range, columns, style, row counts)
- get-data: Get actual table DATA as 2D array (use visibleOnly=true for filtered data)
- add-to-datamodel: Add an existing worksheet table to Power Pivot for DAX analysis
- append: Add rows to existing table (CSV format via style parameter)
- resize: Change table range (expand/contract)
- delete: Remove table (keeps data, removes table formatting)
- **create-from-dax**: Create table populated by a DAX EVALUATE query from Data Model
- **update-dax**: Update an existing DAX-backed table's query
- **get-dax**: Get the DAX query behind a DAX-backed table
**DAX-backed tables** (NEW):
Create worksheet tables populated by DAX EVALUATE queries against the Data Model.
Perfect for creating summary/report tables with aggregated data.
```
Workflow:
1. Have data in Data Model (via excel_table add-to-datamodel or excel_powerquery)
2. Use create-from-dax with a DAX EVALUATE query
3. Table is created on worksheet with query results
4. Use update-dax to change the query, get-dax to inspect it
```
Example DAX queries for create-from-dax:
- `EVALUATE SUMMARIZE('Sales', 'Sales'[Region], "Total", SUM('Sales'[Amount]))`
- `EVALUATE TOPN(10, 'Products', 'Products'[Revenue], DESC)`
- `EVALUATE FILTER('Customers', 'Customers'[Country] = "USA")`
**add-to-datamodel behavior**:
- Only works on Excel Tables (ListObjects), not plain ranges
- Table appears in Power Pivot with same name
- After adding, use excel_datamodel to create DAX measures
- Idempotent: calling on already-added table is a no-op
**When to use which tool**:
| Goal | Tool |
|------|------|
| Create/manage worksheet tables | excel_table |
| Add worksheet table to Power Pivot | excel_table (add-to-datamodel) |
| Import external data to Data Model | excel_powerquery (loadDestination='data-model') |
| Create DAX measures | excel_datamodel |
| **Display DAX query results** | `excel_table create-from-dax` |
| **Interactive analysis** | excel_pivottable |
**create-from-dax vs PivotTable**:
| Use create-from-dax when | Use PivotTable when |
|--------------------------|---------------------|
| Displaying flat query results | User needs drill-down/filtering |
| Static reports/snapshots | Interactive analysis required |
| Data will be used in formulas | Cross-tabulation (rows × columns) |
| Clean tabular display needed | User will regroup/pivot data |
**Common mistakes**:
- Trying to create DAX measures without first adding table to Data Model
- Using excel_datamodel to add tables (it only manages existing Data Model tables)
- Confusing get-data (returns cell values) with read (returns metadata)
- Forgetting hasHeaders parameter when creating tables from headerless data
**Server-specific quirks**:
- Style parameter is overloaded: table style name OR total function OR CSV data (context-dependent)
- visibleOnly parameter only applies to get-data action
- Table names must be unique within workbook (Excel requirement)
