# Creating CDS Views with Low-Level Handlers
This guide demonstrates how to create a CDS view (DDL source) using low-level MCP handlers.
## Overview
CDS views are created as DDL source objects. The workflow is similar to classes:
```
GetSession → ValidateView → CreateView → LockView → UpdateView → UnlockView → ActivateView
```
## Step-by-Step Workflow
### Step 1: Get Session
Obtain a session ID and session state.
**Tool**: `GetSession`
**Request**:
```json
{
"force_new": false
}
```
**Response**:
```json
{
"success": true,
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "SAP_SESSIONID_E19_100=xyz...",
"csrf_token": "AbCdEf123456",
"cookie_store": {}
}
}
```
---
### Step 2: Validate View Name
Check if the view name is valid and available.
**Tool**: `ValidateViewLow`
**Request**:
```json
{
"view_name": "ZCDS_MY_VIEW",
"package_name": "ZOK_LOCAL",
"description": "Test CDS view",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**Response** (Success):
```json
{
"success": true,
"view_name": "ZCDS_MY_VIEW",
"validation_result": {
"valid": true
},
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
---
### Step 3: Create View
Create the view structure.
**Tool**: `CreateViewLow`
**Request**:
```json
{
"view_name": "ZCDS_MY_VIEW",
"description": "Test CDS view for demonstration",
"package_name": "ZOK_LOCAL",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**Response**:
```json
{
"success": true,
"view_name": "ZCDS_MY_VIEW",
"package_name": "ZOK_LOCAL",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
},
"message": "View ZCDS_MY_VIEW created successfully..."
}
```
---
### Step 4: Lock View
Acquire an exclusive lock on the view.
**Tool**: `LockViewLow`
**Request**:
```json
{
"view_name": "ZCDS_MY_VIEW",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**Response**:
```json
{
"success": true,
"view_name": "ZCDS_MY_VIEW",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"lock_handle": "BD53F3688D0F164CA3ADF06FD43C39E1CC1C3B32",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**CRITICAL**:
- Save `lock_handle` - it's required for Update and Unlock operations
- **Save `session_id` and `session_state` from this response** - they MUST be used in Update and Unlock operations
- **Lock, Update, and Unlock MUST use the same session** - use the `session_id` and `session_state` from this Lock response
---
### Step 5: Update View (DDL Source)
Add the DDL source code for the CDS view.
**Tool**: `UpdateViewLow`
**Request**:
```json
{
"view_name": "ZCDS_MY_VIEW",
"source_code": "@AbapCatalog.viewEnhancementCategory: [#NONE]\n@AccessControl.authorizationCheck: #CHECK\n@EndUserText.label: 'My Test CDS View'\n@Metadata.ignorePropagatedAnnotations: true\n@Metadata.allowExtensions: true\n@Search.searchable: true\ndefine view entity ZCDS_MY_VIEW\n as select from sflight\n{\n key carrid,\n key connid,\n key fldate,\n price,\n currency,\n planetype\n}\nwhere\n carrid = 'LH'",
"lock_handle": "BD53F3688D0F164CA3ADF06FD43C39E1CC1C3B32",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**Response**:
```json
{
"success": true,
"view_name": "ZCDS_MY_VIEW",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
},
"message": "View ZCDS_MY_VIEW updated successfully..."
}
```
**CRITICAL**:
- **MUST use the same `session_id` and `session_state` from the Lock operation** - Update must be in the same session as Lock
- DDL source must be valid CDS view syntax
- Use `\n` for line breaks in JSON strings
- Update `session_state` from response for subsequent operations
---
### Step 6: Unlock View
Release the lock.
**Tool**: `UnlockViewLow`
**Request**:
```json
{
"view_name": "ZCDS_MY_VIEW",
"lock_handle": "BD53F3688D0F164CA3ADF06FD43C39E1CC1C3B32",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**Response**:
```json
{
"success": true,
"view_name": "ZCDS_MY_VIEW",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
---
### Step 7: Activate View
Activate the CDS view.
**Tool**: `ActivateViewLow`
**Request**:
```json
{
"view_name": "ZCDS_MY_VIEW",
"session_id": "a1b2c3d4e5f6789012345678901234567890abcd",
"session_state": {
"cookies": "...",
"csrf_token": "...",
"cookie_store": {}
}
}
```
**Response**:
```json
{
"success": true,
"view_name": "ZCDS_MY_VIEW",
"activation_result": {
"status": "success",
"warnings": [],
"errors": []
},
"message": "View ZCDS_MY_VIEW activated successfully"
}
```
---
## Complete Example
```python
# Step 1: Get Session
session = get_session()
session_id = session["session_id"]
session_state = session["session_state"]
try:
# Step 2: Validate
validation = validate_view(
view_name="ZCDS_MY_VIEW",
package_name="ZOK_LOCAL",
session_id=session_id,
session_state=session_state
)
if not validation["validation_result"]["valid"]:
raise Error(f"Validation failed: {validation['validation_result']['message']}")
session_state = validation["session_state"]
# Step 3: Create
create_result = create_view(
view_name="ZCDS_MY_VIEW",
description="Test CDS view",
package_name="ZOK_LOCAL",
session_id=session_id,
session_state=session_state
)
session_state = create_result["session_state"]
# Step 4: Lock
lock_result = lock_view(
view_name="ZCDS_MY_VIEW",
session_id=session_id,
session_state=session_state
)
lock_handle = lock_result["lock_handle"]
# CRITICAL: Save session_id and session_state from Lock response
# These MUST be used in Update and Unlock operations
lock_session_id = lock_result["session_id"]
lock_session_state = lock_result["session_state"]
try:
# Step 5: Update
ddl_source = """@AbapCatalog.viewEnhancementCategory: [#NONE]
@AccessControl.authorizationCheck: #CHECK
@EndUserText.label: 'My Test CDS View'
define view entity ZCDS_MY_VIEW
as select from sflight
{
key carrid,
key connid,
key fldate,
price,
currency
}
where
carrid = 'LH'"""
# CRITICAL: Use session_id and session_state from Lock response
update_result = update_view(
view_name="ZCDS_MY_VIEW",
source_code=ddl_source,
lock_handle=lock_handle,
session_id=lock_session_id, # ← From Lock response
session_state=lock_session_state # ← From Lock response
)
session_state = update_result["session_state"]
finally:
# Step 6: Unlock
# CRITICAL: Use session_id and session_state from Lock response
unlock_result = unlock_view(
view_name="ZCDS_MY_VIEW",
lock_handle=lock_handle,
session_id=lock_session_id, # ← From Lock response
session_state=lock_session_state # ← From Lock response
)
session_state = unlock_result["session_state"]
# Step 7: Activate
activate_result = activate_view(
view_name="ZCDS_MY_VIEW",
session_id=session_id,
session_state=session_state
)
print("✅ CDS view created and activated successfully!")
except Error as e:
print(f"❌ Error: {e}")
if 'lock_handle' in locals():
try:
unlock_view(
view_name="ZCDS_MY_VIEW",
lock_handle=lock_handle,
session_id=session_id,
session_state=session_state
)
except:
pass
```
## CDS View DDL Source Format
CDS views use DDL (Data Definition Language) syntax. Example:
```abap
@AbapCatalog.viewEnhancementCategory: [#NONE]
@AccessControl.authorizationCheck: #CHECK
@EndUserText.label: 'My CDS View'
@Metadata.ignorePropagatedAnnotations: true
@Metadata.allowExtensions: true
@Search.searchable: true
define view entity ZCDS_MY_VIEW
as select from sflight
{
key carrid,
key connid,
key fldate,
price,
currency,
planetype
}
where
carrid = 'LH'
```
## Common Errors
### Error: "View already exists"
- **Solution**: Delete the existing view or choose a different name
### Error: "DDL syntax error"
- **Solution**: Validate your DDL source code syntax. Check annotations and SQL syntax.
### Error: "Invalid lock handle"
- **Solution**:
- **CRITICAL**: You MUST use the `session_id` and `session_state` from the Lock response in Update and Unlock operations
- Lock, Update, and Unlock MUST be in the same session
- Always save `session_id` and `session_state` from Lock response and pass them to Update and Unlock
## Best Practices
1. **Validate DDL syntax** - Ensure your DDL source is valid before updating
2. **Use proper annotations** - Include required annotations like `@AbapCatalog`, `@EndUserText`
3. **Test activation** - Always activate after unlock to check for syntax errors
4. **Handle errors** - Always unlock in finally blocks
## Related Tools
- `GetSession` - Get session ID and state
- `ValidateViewLow` - Validate view name
- `CreateViewLow` - Create view structure
- `LockViewLow` - Lock view for modification
- `UpdateViewLow` - Update DDL source code
- `UnlockViewLow` - Release lock
- `ActivateViewLow` - Activate view
## See Also
- [Creating Classes](./CREATING_CLASSES.md) - Similar workflow for classes
- [Session Management](./SESSION_MANAGEMENT.md) - Understanding sessions
- [Common Patterns](./COMMON_PATTERNS.md) - Reusable patterns
