# Tool: build_dependency_graph
## Purpose
Builds a visual dependency graph showing relationships between Snowflake objects, useful for understanding data flow and identifying circular dependencies.
## Parameters
| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| `database` | string | Yes | Database name to analyze |
| `output_dir` | string | No | Output directory for graph files (default: "./dependencies") |
| `format` | string | No | Output format: "dot", "json", or "both" (default: "both") |
| `include_views` | boolean | No | Include views in dependency graph (default: true) |
| `include_functions` | boolean | No | Include functions in dependency graph (default: false) |
| `max_depth` | integer | No | Maximum dependency depth to analyze (default: 5) |
## Returns
Returns a dictionary containing:
- `output_dir`: Directory where graph files were saved
- `files_created`: List of files created
- `summary`: Summary statistics of the dependency graph
- `circular_dependencies`: List of detected circular dependencies
- `total_objects`: Total number of objects analyzed
## Examples
### Basic Dependency Graph
```json
{
"tool": "build_dependency_graph",
"arguments": {
"database": "MY_DATABASE"
}
}
```
**Expected Output**:
```json
{
"output_dir": "./dependencies",
"files_created": [
"dependency_graph.dot",
"dependency_graph.json"
],
"summary": {
"total_objects": 25,
"relationships": 45,
"circular_dependencies": 2
},
"circular_dependencies": [
{
"cycle": ["TABLE_A", "VIEW_B", "TABLE_C", "TABLE_A"],
"severity": "high"
}
],
"total_objects": 25
}
```
### DOT Format Only
```json
{
"tool": "build_dependency_graph",
"arguments": {
"database": "MY_DATABASE",
"format": "dot",
"output_dir": "./graphs"
}
}
```
### Exclude Views
```json
{
"tool": "build_dependency_graph",
"arguments": {
"database": "MY_DATABASE",
"include_views": false,
"max_depth": 3
}
}
```
## Common Use Cases
### Architecture Documentation
Generate visual diagrams of your data architecture for documentation.
### Circular Dependency Detection
Identify problematic circular dependencies that can cause issues.
### Impact Analysis
Understand the scope of changes by visualizing dependencies.
### Data Lineage Visualization
Create visual representations of data flow through your system.
## Troubleshooting
### Database Not Found
**Error**: `Database 'MY_DATABASE' not found`
**Solution**:
- Verify database name spelling
- Check database exists in Snowflake
- Ensure proper permissions
### No Dependencies Found
**Error**: `No dependencies found`
**Solution**:
- Check if objects have relationships
- Verify include_views/include_functions settings
- Increase max_depth if needed
### Performance Issues
**Error**: `Query timeout`
**Solution**:
- Reduce max_depth
- Exclude views or functions
- Use smaller database subset
### Output Directory Issues
**Error**: `Cannot write to output directory`
**Solution**:
- Check directory permissions
- Ensure directory exists
- Use absolute path if needed
## Related Tools
- [build_catalog](build_catalog.md) - Build catalog before dependency analysis
- [query_lineage](query_lineage.md) - Analyze specific object lineage
- [get_catalog_summary](get_catalog_summary.md) - Check catalog status
- [preview_table](preview_table.md) - Preview table structure
## Output Files
### DOT File
Graphviz format for visualization:
```dot
digraph dependencies {
"TABLE_A" -> "VIEW_B";
"VIEW_B" -> "TABLE_C";
"TABLE_C" -> "TABLE_A" [color=red, style=dashed];
}
```
### JSON File
Structured dependency data:
```json
{
"nodes": [
{"id": "TABLE_A", "type": "table"},
{"id": "VIEW_B", "type": "view"}
],
"edges": [
{"from": "TABLE_A", "to": "VIEW_B", "type": "dependency"}
]
}
```
## Notes
- Requires a built catalog for analysis
- DOT files can be rendered with Graphviz
- Circular dependencies are highlighted in red
- Performance scales with database size and complexity
- Output files are overwritten on each run
