docs: use single quotes for strings in SQL restrictions

PostgreSQL interprets double quotes as identifier references, not string
literals. Changed all examples to use the portable pattern:
  Table & "field = 'value'"

instead of the MySQL-only pattern:
  Table & 'field = "value"'

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

src/explanation/computation-model.md

@@ -106,10 +106,10 @@ Each auto-populated table has an associated jobs table:
 Segmentation.jobs()
 
 # View errors
-Segmentation.jobs & 'status = "error"'
+Segmentation.jobs & "status = 'error'"
 
 # Clear errors to retry
-(Segmentation.jobs & 'status = "error"').delete()
+(Segmentation.jobs & "status = 'error'").delete()
 ```
 
 ### Parallel Execution
@@ -134,13 +134,13 @@ Jobs are reserved atomically—no two workers process the same key.
 Segmentation.populate(suppress_errors=True)
 
 # Check what failed
-errors = (Segmentation.jobs & 'status = "error"').to_dicts()
+errors = (Segmentation.jobs & "status = 'error'").to_dicts()
 
 # Clear specific error to retry
 (Segmentation.jobs & error_key).delete()
 
 # Clear all errors
-(Segmentation.jobs & 'status = "error"').delete()
+(Segmentation.jobs & "status = 'error'").delete()
 ```
 
 ## Imported vs. Computed

src/explanation/query-algebra.md

@@ -34,13 +34,13 @@ Filter entities based on conditions.
 
 ```python
 # Mice born after 2024
-Mouse & 'date_of_birth > "2024-01-01"'
+Mouse & "date_of_birth > '2024-01-01'"
 
 # Sessions for a specific mouse
 Session & {'mouse_id': 42}
 
 # Sessions matching a query
-Session & (Mouse & 'strain = "C57BL/6"')
+Session & (Mouse & "strain = 'C57BL/6'")
 ```
 
 ### Exclude (`-`)
@@ -221,7 +221,7 @@ Operators compose freely:
 ```python
 # Complex query
 result = (
-    (Mouse & 'strain = "C57BL/6"')  # Filter mice
+    (Mouse & "strain = 'C57BL/6'")  # Filter mice
     * Session                        # Join sessions
     * Scan                           # Join scans
     .proj('scan_date', 'depth')      # Select attributes

src/how-to/delete-data.md

@@ -11,7 +11,7 @@ Delete rows matching a restriction:
 (Subject & {'subject_id': 'M001'}).delete()
 
 # Delete with condition
-(Session & 'session_date < "2024-01-01"').delete()
+(Session & "session_date < '2024-01-01'").delete()
 ```
 
 ## Cascade Behavior
@@ -141,14 +141,14 @@ Delete without cascade (fails if dependent rows exist):
 ### By Condition
 
 ```python
-(Trial & 'outcome = "miss"').delete()
+(Trial & "outcome = 'miss'").delete()
 ```
 
 ### By Join
 
 ```python
 # Delete trials from sessions before 2024
-old_sessions = Session & 'session_date < "2024-01-01"'
+old_sessions = Session & "session_date < '2024-01-01'"
 (Trial & old_sessions).delete()
 ```
 

src/how-to/handle-errors.md

@@ -55,7 +55,7 @@ Target specific failed jobs:
 
 ```python
 # Clear one error
-(ProcessedData.jobs & key & 'status="error"').delete()
+(ProcessedData.jobs & key & "status='error'").delete()
 
 # Retry just that key
 ProcessedData.populate(key, reserve_jobs=True)

src/how-to/migrate-to-v20.md

@@ -385,7 +385,7 @@ def test_query_patterns(test_schema):
     assert len(mice) == 1
 
     # Test restriction
-    male_mice = Mouse & 'sex="M"'
+    male_mice = Mouse & "sex='M'"
     assert len(male_mice) == 1
 ```
 
@@ -417,7 +417,7 @@ def test_full_pipeline(test_schema):
     assert len(Analysis()) > 0
 
     # 4. Test queries work
-    alice_sessions = Session & 'experimenter="Alice"'
+    alice_sessions = Session & "experimenter='Alice'"
     assert len(alice_sessions) == 1
 ```
 

src/how-to/run-computations.md

@@ -39,7 +39,7 @@ ProcessedData.populate(limit=100)
 ProcessedData.populate(suppress_errors=True)
 
 # Check what failed
-failed = ProcessedData.jobs & 'status = "error"'
+failed = ProcessedData.jobs & "status = 'error'"
 print(failed)
 
 # Clear errors to retry

src/reference/operators.md

@@ -39,7 +39,7 @@ Session & [{'subject_id': 'M001'}, {'subject_id': 'M002'}]
 
 **Chaining**: Multiple restrictions combine with AND:
 ```python
-Session & "duration > 30" & {'experimenter': 'alice'}
+Session & "duration > 30" & {"experimenter": "alice"}
 ```
 
 ### Top N Rows (`dj.Top`)

src/reference/specs/fetch-api.md

@@ -186,7 +186,7 @@ arr = Experiment().to_arrays()
 
 ```python
 # Get recent experiments, sorted by date
-recent = (Experiment() & 'date > "2024-01-01"').to_pandas(
+recent = (Experiment() & "date > '2024-01-01'").to_pandas(
     order_by='date DESC',
     limit=100
 )

src/reference/specs/table-declaration.md

@@ -195,7 +195,7 @@ results = MyTable.proj('result', '_job_start_time').to_dicts()
 row = (MyTable & key).fetch1('result', '_job_start_time')
 
 # String restriction works with hidden attributes
-MyTable & '_job_start_time > "2024-01-01"'
+MyTable & "_job_start_time > '2024-01-01'"
 
 # Dict restriction IGNORES hidden attributes
 MyTable & {'_job_start_time': some_date}  # no effect

src/reference/specs/virtual-schemas.md

@@ -118,7 +118,7 @@ lab = dj.virtual_schema('my_lab_schema')
 
 # Access tables as attributes (classes)
 lab.Subject.fetch()
-lab.Session & 'subject_id="M001"'
+lab.Session & "subject_id='M001'"
 
 # Full query algebra supported
 (lab.Session * lab.Subject).fetch()
@@ -173,7 +173,7 @@ schema.make_classes()
 
 # Now table classes are available in local namespace
 Subject.fetch()
-Session & 'date > "2024-01-01"'
+Session & "date > '2024-01-01'"
 ```
 
 **Parameters:**