Document some possible error messages
Andrew Brookins
3 years ago
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# Errors
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This page lists errors that Redis OM might generate while you're using it, with more context about the error.
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## E1
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> In order to query on a list field, you must define the contents of the list with a type annotation, like: orders: List[Order].
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You will see this error if you try to use an "IN" query, e.g., `await TarotWitch.find(TarotWitch.tarot_cards << "death").all()`, on a field that is not a list.
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In this example, `TarotWitch.tarot_cards` is a list, so the query works:
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```python
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from typing import List
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from redis_om import JsonModel, Field
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class TarotWitch(JsonModel):
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tarot_cards: List[str] = Field(index=True)
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```
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But if `tarot_cards` was _not_ a list, trying to query with `<<` would have resulted in this error.
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## E2
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> You tried sort by {field_name}, but {self.model} does not define that field as sortable.
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You tried to sort query results by a field that is not sortable. Here is how you mark a field as sortable:
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```python
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from typing import List
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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age: int = Field(index=True, sortable=True)
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```
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**NOTE:** Only an indexed field can be sortable.
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## E3
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>You tried to do a full-text search on the field '{field.name}', but the field is not indexed for full-text search. Use the full_text_search=True option.
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You can make a full-text search with the module (`%`) operator. Such a query looks like this:
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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bio: str = Field(index=True, full_text_search=True, default="")
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Member.find(Member.bio % "beaches").all()
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```
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If you see this error, it means that the field you are querying (`bio` in the example) is not indexed for full-text search. Make sure you're marking the field both `index=True` and `full_text_search=True`, as in the example.
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## E4
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> Only lists and tuples are supported for multi-value fields.
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This means that you marked a field as `index=True`, but the field is not a type that Redis OM can actually index.
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Specifically, you probably used a _subscripted_ annotation, like `Dict[str, str]`. The only subscripted types that OM can index are `List` and `Tuple`.
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## E5
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> Only equals (=), not-equals (!=), and like() comparisons are supported for TEXT fields.
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You are querying a field you marked as indexed for full-text search. You can only query such fields with the operators for equality (==), non-equality (!=), and like `(%)`.
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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bio: str = Field(index=True, full_text_search=True, default="")
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# Equality
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Member.find(Member.bio == "Programmer").all()
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# Non-equality
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Member.find(Member.bio != "Programmer").all()
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# Like (full-text search). This stems "programming"
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# to find any matching terms with the same stem,
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# "program".
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Member.find(Member.bio % "programming").all()
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```
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## E6
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> You tried to query by a field ({field_name}) that isn't indexed.
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You wrote a query using a model field that you did not make indexed. You can only query indexed fields. Here is example code that would generate this error:
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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first_name: str
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bio: str = Field(index=True, full_text_search=True, default="")
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# Raises a QueryNotSupportedError because we did not make
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# `first_name` indexed!
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Member.find(Member.first_name == "Andrew").all()
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```
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Fix this by making the field indexed:
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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first_name: str = Field(index=True)
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bio: str = Field(index=True, full_text_search=True, default="")
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# Raises a QueryNotSupportedError because we did not make
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# `first_name` indexed!
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Member.find(Member.first_name == "Andrew").all()
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```
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## E7
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> A query expression should start with either a field or an expression enclosed in parentheses.
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We got confused trying to parse your query expression. It's not you, it's us! Some code examples might help...
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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first_name: str = Field(index=True)
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last_name: str = Field(index=True)
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# Queries with a single operator are usually simple:
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Member.find(Member.first_name == "Andrew").all()
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# If you want to add multiple conditions, you can AND
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# them together by including the conditions one after
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# another as arguments.
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Member.find(Member.first_name=="Andrew",
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Member.last_name=="Brookins").all()
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# Alternatively, you can separate the conditions with
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# parenthesis and use an explicit AND.
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Member.find(
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(Member.first_name == "Andrew") & ~(Member.last_name == "Brookins")
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).all()
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# You can't use `!` to say NOT. Instead, use `~`.
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Member.find(
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(Member.first_name == "Andrew") &
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~(Member.last_name == "Brookins") # <- Notice, this one is NOT now!
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).all()
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# Parenthesis are key to building more complex queries,
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# like this one.
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Member.find(
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~(Member.first_name == "Andrew")
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& ((Member.last_name == "Brookins") | (Member.last_name == "Smith"))
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).all()
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# If you're confused about how Redis OM interprets a query,
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# use the `tree()` method to visualize the expression tree
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# for a `FindQuery`.
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query = Member.find(
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~(Member.first_name == "Andrew")
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& ((Member.last_name == "Brookins") | (Member.last_name == "Smith"))
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)
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print(query.expression.tree)
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"""
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┌first_name
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┌NOT EQ┤
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| └Andrew
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AND┤
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| ┌last_name
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| ┌EQ┤
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| | └Brookins
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└OR┤
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| ┌last_name
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└EQ┤
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└Smith
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"""
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```
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## E8
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> You can only combine two query expressions with AND (&) or OR (|).
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The only two operators you can use to combine expressions in a query
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are `&` and `|`. You may have accidentally used another operator,
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or Redis OM might be confused. Make sure you are using parentheses
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to organize your query expressions.
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If you are trying to use "NOT," you can do that by prefixing a query
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with the `~` operator, like this:
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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first_name: str = Field(index=True)
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last_name: str = Field(index=True)
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# Find people who are not named Andrew.
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Member.find(~(Member.first_name == "Andrew")).all()
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```
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Note that this form requires parenthesis around the expression
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that you are "negating." Of course, this example makes more sense
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with `!=`:
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```python
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from redis_om import JsonModel, Field
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class Member(JsonModel):
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first_name: str = Field(index=True)
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last_name: str = Field(index=True)
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# Find people who are not named Andrew.
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Member.find(Member.first_name != "Andrew").all()
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```
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Still, `~` is useful to negate groups of expressions
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surrounded by parentheses.
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