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+"""
+Defines the 'Collection' class
+
+Importing from the `vecs.collection` directly is not supported.
+All public classes, enums, and functions are re-exported by the top level `vecs` module.
+"""
+
+from __future__ import annotations
+
+import math
+import uuid
+import warnings
+from dataclasses import dataclass
+from enum import Enum
+from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Tuple, Union
+
+from flupy import flu
+from pgvector.sqlalchemy import Vector
+from sqlalchemy import (
+    Column,
+    MetaData,
+    String,
+    Table,
+    and_,
+    cast,
+    delete,
+    func,
+    or_,
+    select,
+    text,
+)
+from sqlalchemy.dialects import postgresql
+
+from vecs.adapter import Adapter, AdapterContext, NoOp
+from vecs.exc import (
+    ArgError,
+    CollectionAlreadyExists,
+    CollectionNotFound,
+    FilterError,
+    MismatchedDimension,
+    Unreachable,
+)
+
+if TYPE_CHECKING:
+    from vecs.client import Client
+
+
+MetadataValues = Union[str, int, float, bool, List[str]]
+Metadata = Dict[str, MetadataValues]
+Numeric = Union[int, float, complex]
+Record = Tuple[str, Iterable[Numeric], Metadata]
+
+
+class IndexMethod(str, Enum):
+    """
+    An enum representing the index methods available.
+
+    This class currently only supports the 'ivfflat' method but may
+    expand in the future.
+
+    Attributes:
+        auto (str): Automatically choose the best available index method.
+        ivfflat (str): The ivfflat index method.
+        hnsw (str): The hnsw index method.
+    """
+
+    auto = "auto"
+    ivfflat = "ivfflat"
+    hnsw = "hnsw"
+
+
+class IndexMeasure(str, Enum):
+    """
+    An enum representing the types of distance measures available for indexing.
+
+    Attributes:
+        cosine_distance (str): The cosine distance measure for indexing.
+        l2_distance (str): The Euclidean (L2) distance measure for indexing.
+        max_inner_product (str): The maximum inner product measure for indexing.
+    """
+
+    cosine_distance = "cosine_distance"
+    l2_distance = "l2_distance"
+    max_inner_product = "max_inner_product"
+    l1_distance = "l1_distance"
+
+
+@dataclass
+class IndexArgsIVFFlat:
+    """
+    A class for arguments that can optionally be supplied to the index creation
+    method when building an IVFFlat type index.
+
+    Attributes:
+        nlist (int): The number of IVF centroids that the index should use
+    """
+
+    n_lists: int
+
+
+@dataclass
+class IndexArgsHNSW:
+    """
+    A class for arguments that can optionally be supplied to the index creation
+    method when building an HNSW type index.
+
+    Ref: https://github.com/pgvector/pgvector#index-options
+
+    Both attributes are Optional in case the user only wants to specify one and
+    leave the other as default
+
+    Attributes:
+        m (int): Maximum number of connections per node per layer (default: 16)
+        ef_construction (int): Size of the dynamic candidate list for
+            constructing the graph (default: 64)
+    """
+
+    m: Optional[int] = 16
+    ef_construction: Optional[int] = 64
+
+
+INDEX_MEASURE_TO_OPS = {
+    # Maps the IndexMeasure enum options to the SQL ops string required by
+    # the pgvector `create index` statement
+    IndexMeasure.cosine_distance: "vector_cosine_ops",
+    IndexMeasure.l2_distance: "vector_l2_ops",
+    IndexMeasure.max_inner_product: "vector_ip_ops",
+    IndexMeasure.l1_distance: "vector_l1_ops",
+}
+
+INDEX_MEASURE_TO_SQLA_ACC = {
+    IndexMeasure.cosine_distance: lambda x: x.cosine_distance,
+    IndexMeasure.l2_distance: lambda x: x.l2_distance,
+    IndexMeasure.max_inner_product: lambda x: x.max_inner_product,
+    IndexMeasure.l1_distance: lambda x: x.l1_distance,
+}
+
+
+class Collection:
+    """
+    The `vecs.Collection` class represents a collection of vectors within a PostgreSQL database with pgvector support.
+    It provides methods to manage (create, delete, fetch, upsert), index, and perform similarity searches on these vector collections.
+
+    The collections are stored in separate tables in the database, with each vector associated with an identifier and optional metadata.
+
+    Example usage:
+
+        with vecs.create_client(DB_CONNECTION) as vx:
+            collection = vx.create_collection(name="docs", dimension=3)
+            collection.upsert([("id1", [1, 1, 1], {"key": "value"})])
+            # Further operations on 'collection'
+
+    Public Attributes:
+        name: The name of the vector collection.
+        dimension: The dimension of vectors in the collection.
+
+    Note: Some methods of this class can raise exceptions from the `vecs.exc` module if errors occur.
+    """
+
+    def __init__(
+        self,
+        name: str,
+        dimension: int,
+        client: Client,
+        adapter: Optional[Adapter] = None,
+    ):
+        """
+        Initializes a new instance of the `Collection` class.
+
+        During expected use, developers initialize instances of `Collection` using the
+        `vecs.Client` with `vecs.Client.create_collection(...)` rather than directly.
+
+        Args:
+            name (str): The name of the collection.
+            dimension (int): The dimension of the vectors in the collection.
+            client (Client): The client to use for interacting with the database.
+        """
+        self.client = client
+        self.name = name
+        self.dimension = dimension
+        self.table = build_table(name, client.meta, dimension)
+        self._index: Optional[str] = None
+        self.adapter = adapter or Adapter(steps=[NoOp(dimension=dimension)])
+
+        reported_dimensions = set(
+            [
+                x
+                for x in [
+                    dimension,
+                    adapter.exported_dimension if adapter else None,
+                ]
+                if x is not None
+            ]
+        )
+        if len(reported_dimensions) == 0:
+            raise ArgError("One of dimension or adapter must provide a dimension")
+        elif len(reported_dimensions) > 1:
+            raise MismatchedDimension(
+                "Dimensions reported by adapter, dimension, and collection do not match"
+            )
+
+    def __repr__(self):
+        """
+        Returns a string representation of the `Collection` instance.
+
+        Returns:
+            str: A string representation of the `Collection` instance.
+        """
+        return f'vecs.Collection(name="{self.name}", dimension={self.dimension})'
+
+    def __len__(self) -> int:
+        """
+        Returns the number of vectors in the collection.
+
+        Returns:
+            int: The number of vectors in the collection.
+        """
+        with self.client.Session() as sess:
+            with sess.begin():
+                stmt = select(func.count()).select_from(self.table)
+                return sess.execute(stmt).scalar() or 0
+
+    def _create_if_not_exists(self):
+        """
+        PRIVATE
+
+        Creates a new collection in the database if it doesn't already exist
+
+        Returns:
+            Collection: The found or created collection.
+        """
+        query = text(
+            f"""
+        select
+            relname as table_name,
+            atttypmod as embedding_dim
+        from
+            pg_class pc
+            join pg_attribute pa
+                on pc.oid = pa.attrelid
+        where
+            pc.relnamespace = 'vecs'::regnamespace
+            and pc.relkind = 'r'
+            and pa.attname = 'vec'
+            and not pc.relname ^@ '_'
+            and pc.relname = :name
+        """
+        ).bindparams(name=self.name)
+        with self.client.Session() as sess:
+            query_result = sess.execute(query).fetchone()
+
+            if query_result:
+                _, collection_dimension = query_result
+            else:
+                collection_dimension = None
+
+        reported_dimensions = set(
+            [x for x in [self.dimension, collection_dimension] if x is not None]
+        )
+        if len(reported_dimensions) > 1:
+            raise MismatchedDimension(
+                "Dimensions reported by adapter, dimension, and existing collection do not match"
+            )
+
+        if not collection_dimension:
+            self.table.create(self.client.engine)
+
+        return self
+
+    def _create(self):
+        """
+        PRIVATE
+
+        Creates a new collection in the database. Raises a `vecs.exc.CollectionAlreadyExists`
+        exception if a collection with the specified name already exists.
+
+        Returns:
+            Collection: The newly created collection.
+        """
+
+        collection_exists = self.__class__._does_collection_exist(
+            self.client, self.name
+        )
+        if collection_exists:
+            raise CollectionAlreadyExists(
+                "Collection with requested name already exists"
+            )
+        self.table.create(self.client.engine)
+
+        unique_string = str(uuid.uuid4()).replace("-", "_")[0:7]
+        with self.client.Session() as sess:
+            sess.execute(
+                text(
+                    f"""
+                    create index ix_meta_{unique_string}
+                      on vecs."{self.table.name}"
+                      using gin ( metadata jsonb_path_ops )
+                    """
+                )
+            )
+        return self
+
+    def _drop(self):
+        """
+        PRIVATE
+
+        Deletes the collection from the database. Raises a `vecs.exc.CollectionNotFound`
+        exception if no collection with the specified name exists.
+
+        Returns:
+            Collection: The deleted collection.
+        """
+        from sqlalchemy.schema import DropTable
+
+        with self.client.Session() as sess:
+            sess.execute(DropTable(self.table, if_exists=True))
+            sess.commit()
+
+        return self
+
+    def upsert(
+        self, records: Iterable[Tuple[str, Any, Metadata]], skip_adapter: bool = False
+    ) -> None:
+        """
+        Inserts or updates *vectors* records in the collection.
+
+        Args:
+            records (Iterable[Tuple[str, Any, Metadata]]): An iterable of content to upsert.
+                Each record is a tuple where:
+                  - the first element is a unique string identifier
+                  - the second element is an iterable of numeric values or relevant input type for the
+                    adapter assigned to the collection
+                  - the third element is metadata associated with the vector
+
+            skip_adapter (bool): Should the adapter be skipped while upserting. i.e. if vectors are being
+                provided, rather than a media type that needs to be transformed
+        """
+
+        chunk_size = 500
+
+        if skip_adapter:
+            pipeline = flu(records).chunk(chunk_size)
+        else:
+            # Construct a lazy pipeline of steps to transform and chunk user input
+            pipeline = flu(self.adapter(records, AdapterContext("upsert"))).chunk(
+                chunk_size
+            )
+
+        with self.client.Session() as sess:
+            with sess.begin():
+                for chunk in pipeline:
+                    stmt = postgresql.insert(self.table).values(chunk)
+                    stmt = stmt.on_conflict_do_update(
+                        index_elements=[self.table.c.id],
+                        set_=dict(
+                            vec=stmt.excluded.vec, metadata=stmt.excluded.metadata
+                        ),
+                    )
+                    sess.execute(stmt)
+        return None
+
+    def fetch(self, ids: Iterable[str]) -> List[Record]:
+        """
+        Fetches vectors from the collection by their identifiers.
+
+        Args:
+            ids (Iterable[str]): An iterable of vector identifiers.
+
+        Returns:
+            List[Record]: A list of the fetched vectors.
+        """
+        if isinstance(ids, str):
+            raise ArgError("ids must be a list of strings")
+
+        chunk_size = 12
+        records = []
+        with self.client.Session() as sess:
+            with sess.begin():
+                for id_chunk in flu(ids).chunk(chunk_size):
+                    stmt = select(self.table).where(self.table.c.id.in_(id_chunk))
+                    chunk_records = sess.execute(stmt)
+                    records.extend(chunk_records)
+        return records
+
+    def delete(
+        self, ids: Optional[Iterable[str]] = None, filters: Optional[Metadata] = None
+    ) -> List[str]:
+        """
+        Deletes vectors from the collection by matching filters or ids.
+
+        Args:
+            ids (Iterable[str], optional): An iterable of vector identifiers.
+            filters (Optional[Dict], optional): Filters to apply to the search. Defaults to None.
+
+        Returns:
+            List[str]: A list of the identifiers of the deleted vectors.
+        """
+        if ids is None and filters is None:
+            raise ArgError("Either ids or filters must be provided.")
+
+        if ids is not None and filters is not None:
+            raise ArgError("Either ids or filters must be provided, not both.")
+
+        if isinstance(ids, str):
+            raise ArgError("ids must be a list of strings")
+
+        ids = ids or []
+        filters = filters or {}
+        del_ids = []
+
+        with self.client.Session() as sess:
+            with sess.begin():
+                if ids:
+                    for id_chunk in flu(ids).chunk(12):
+                        stmt = (
+                            delete(self.table)
+                            .where(self.table.c.id.in_(id_chunk))
+                            .returning(self.table.c.id)
+                        )
+                        del_ids.extend(sess.execute(stmt).scalars() or [])
+
+                if filters:
+                    meta_filter = build_filters(self.table.c.metadata, filters)
+                    stmt = (
+                        delete(self.table).where(meta_filter).returning(self.table.c.id)  # type: ignore
+                    )
+                    result = sess.execute(stmt).scalars()
+                    del_ids.extend(result.fetchall())
+
+        return del_ids
+
+    def __getitem__(self, items):
+        """
+        Fetches a vector from the collection by its identifier.
+
+        Args:
+            items (str): The identifier of the vector.
+
+        Returns:
+            Record: The fetched vector.
+        """
+        if not isinstance(items, str):
+            raise ArgError("items must be a string id")
+
+        row = self.fetch([items])
+
+        if row == []:
+            raise KeyError("no item found with requested id")
+        return row[0]
+
+    def query(
+        self,
+        data: Union[Iterable[Numeric], Any],
+        limit: int = 10,
+        filters: Optional[Dict] = None,
+        measure: Union[IndexMeasure, str] = IndexMeasure.cosine_distance,
+        include_value: bool = False,
+        include_metadata: bool = False,
+        *,
+        probes: Optional[int] = None,
+        ef_search: Optional[int] = None,
+        skip_adapter: bool = False,
+    ) -> Union[List[Record], List[str]]:
+        """
+        Executes a similarity search in the collection.
+
+        The return type is dependent on arguments *include_value* and *include_metadata*
+
+        Args:
+            data (Any): The vector to use as the query.
+            limit (int, optional): The maximum number of results to return. Defaults to 10.
+            filters (Optional[Dict], optional): Filters to apply to the search. Defaults to None.
+            measure (Union[IndexMeasure, str], optional): The distance measure to use for the search. Defaults to 'cosine_distance'.
+            include_value (bool, optional): Whether to include the distance value in the results. Defaults to False.
+            include_metadata (bool, optional): Whether to include the metadata in the results. Defaults to False.
+            probes (Optional[Int], optional): Number of ivfflat index lists to query. Higher increases accuracy but decreases speed
+            ef_search (Optional[Int], optional): Size of the dynamic candidate list for HNSW index search. Higher increases accuracy but decreases speed
+            skip_adapter (bool, optional): When True, skips any associated adapter and queries using a literal vector provided to *data*
+
+        Returns:
+            Union[List[Record], List[str]]: The result of the similarity search.
+        """
+
+        if probes is None:
+            probes = 10
+
+        if ef_search is None:
+            ef_search = 40
+
+        if not isinstance(probes, int):
+            raise ArgError("probes must be an integer")
+
+        if probes < 1:
+            raise ArgError("probes must be >= 1")
+
+        if limit > 1000:
+            raise ArgError("limit must be <= 1000")
+
+        # ValueError on bad input
+        try:
+            imeasure = IndexMeasure(measure)
+        except ValueError:
+            raise ArgError("Invalid index measure")
+
+        if not self.is_indexed_for_measure(imeasure):
+            warnings.warn(
+                UserWarning(
+                    f"Query does not have a covering index for {imeasure}. See Collection.create_index"
+                )
+            )
+
+        if skip_adapter:
+            adapted_query = [("", data, {})]
+        else:
+            # Adapt the query using the pipeline
+            adapted_query = [
+                x
+                for x in self.adapter(
+                    records=[("", data, {})], adapter_context=AdapterContext("query")
+                )
+            ]
+
+        if len(adapted_query) != 1:
+            raise ArgError("Failed to produce exactly one query vector from input")
+
+        _, vec, _ = adapted_query[0]
+
+        distance_lambda = INDEX_MEASURE_TO_SQLA_ACC.get(imeasure)
+        if distance_lambda is None:
+            # unreachable
+            raise ArgError("invalid distance_measure")  # pragma: no cover
+
+        distance_clause = distance_lambda(self.table.c.vec)(vec)
+
+        cols = [self.table.c.id]
+
+        if include_value:
+            cols.append(distance_clause)
+
+        if include_metadata:
+            cols.append(self.table.c.metadata)
+
+        stmt = select(*cols)
+        if filters:
+            stmt = stmt.filter(
+                build_filters(self.table.c.metadata, filters)  # type: ignore
+            )
+
+        stmt = stmt.order_by(distance_clause)
+        stmt = stmt.limit(limit)
+
+        with self.client.Session() as sess:
+            with sess.begin():
+                # index ignored if greater than n_lists
+                sess.execute(
+                    text("set local ivfflat.probes = :probes").bindparams(probes=probes)
+                )
+                if self.client._supports_hnsw():
+                    sess.execute(
+                        text("set local hnsw.ef_search = :ef_search").bindparams(
+                            ef_search=ef_search
+                        )
+                    )
+                if len(cols) == 1:
+                    return [str(x) for x in sess.scalars(stmt).fetchall()]
+                return sess.execute(stmt).fetchall() or []
+
+    @classmethod
+    def _list_collections(cls, client: "Client") -> List["Collection"]:
+        """
+        PRIVATE
+
+        Retrieves all collections from the database.
+
+        Args:
+            client (Client): The database client.
+
+        Returns:
+            List[Collection]: A list of all existing collections.
+        """
+
+        query = text(
+            """
+        select
+            relname as table_name,
+            atttypmod as embedding_dim
+        from
+            pg_class pc
+            join pg_attribute pa
+                on pc.oid = pa.attrelid
+        where
+            pc.relnamespace = 'vecs'::regnamespace
+            and pc.relkind = 'r'
+            and pa.attname = 'vec'
+            and not pc.relname ^@ '_'
+        """
+        )
+        xc = []
+        with client.Session() as sess:
+            for name, dimension in sess.execute(query):
+                existing_collection = cls(name, dimension, client)
+                xc.append(existing_collection)
+        return xc
+
+    @classmethod
+    def _does_collection_exist(cls, client: "Client", name: str) -> bool:
+        """
+        PRIVATE
+
+        Checks if a collection with a given name exists within the database
+
+        Args:
+            client (Client): The database client.
+            name (str): The name of the collection
+
+        Returns:
+            Exists: Whether the collection exists or not
+        """
+
+        try:
+            client.get_collection(name)
+            return True
+        except CollectionNotFound:
+            return False
+
+    @property
+    def index(self) -> Optional[str]:
+        """
+        PRIVATE
+
+        Note:
+            The `index` property is private and expected to undergo refactoring.
+            Do not rely on it's output.
+
+        Retrieves the SQL name of the collection's vector index, if it exists.
+
+        Returns:
+            Optional[str]: The name of the index, or None if no index exists.
+        """
+
+        if self._index is None:
+            query = text(
+                """
+            select
+                pi.relname as index_name
+            from
+                pg_class pi                -- index info
+                join pg_index i            -- extend index info
+                  on pi.oid = i.indexrelid
+                join pg_class pt           -- owning table info
+                  on pt.oid = i.indrelid
+            where
+                pi.relnamespace = 'vecs'::regnamespace
+                and pi.relname ilike 'ix_vector%'
+                and pi.relkind = 'i'
+                and pt.relname = :table_name
+            """
+            )
+            with self.client.Session() as sess:
+                ix_name = sess.execute(query, {"table_name": self.name}).scalar()
+            self._index = ix_name
+        return self._index
+
+    def is_indexed_for_measure(self, measure: IndexMeasure):
+        """
+        Checks if the collection is indexed for a specific measure.
+
+        Args:
+            measure (IndexMeasure): The measure to check for.
+
+        Returns:
+            bool: True if the collection is indexed for the measure, False otherwise.
+        """
+
+        index_name = self.index
+        if index_name is None:
+            return False
+
+        ops = INDEX_MEASURE_TO_OPS.get(measure)
+        if ops is None:
+            return False
+
+        if ops in index_name:
+            return True
+
+        return False
+
+    def create_index(
+        self,
+        measure: IndexMeasure = IndexMeasure.cosine_distance,
+        method: IndexMethod = IndexMethod.auto,
+        index_arguments: Optional[Union[IndexArgsIVFFlat, IndexArgsHNSW]] = None,
+        replace=True,
+    ) -> None:
+        """
+        Creates an index for the collection.
+
+        Note:
+            When `vecs` creates an index on a pgvector column in PostgreSQL, it uses a multi-step
+            process that enables performant indexes to be built for large collections with low end
+            database hardware.
+
+            Those steps are:
+
+            - Creates a new table with a different name
+            - Randomly selects records from the existing table
+            - Inserts the random records from the existing table into the new table
+            - Creates the requested vector index on the new table
+            - Upserts all data from the existing table into the new table
+            - Drops the existing table
+            - Renames the new table to the existing tables name
+
+            If you create dependencies (like views) on the table that underpins
+            a `vecs.Collection` the `create_index` step may require you to drop those dependencies before
+            it will succeed.
+
+        Args:
+            measure (IndexMeasure, optional): The measure to index for. Defaults to 'cosine_distance'.
+            method (IndexMethod, optional): The indexing method to use. Defaults to 'auto'.
+            index_arguments: (IndexArgsIVFFlat | IndexArgsHNSW, optional): Index type specific arguments
+            replace (bool, optional): Whether to replace the existing index. Defaults to True.
+
+        Raises:
+            ArgError: If an invalid index method is used, or if *replace* is False and an index already exists.
+        """
+
+        if method not in (IndexMethod.ivfflat, IndexMethod.hnsw, IndexMethod.auto):
+            raise ArgError("invalid index method")
+
+        if index_arguments:
+            # Disallow case where user submits index arguments but uses the
+            # IndexMethod.auto index (index build arguments should only be
+            # used with a specific index)
+            if method == IndexMethod.auto:
+                raise ArgError(
+                    "Index build parameters are not allowed when using the IndexMethod.auto index."
+                )
+            # Disallow case where user specifies one index type but submits
+            # index build arguments for the other index type
+            if (
+                isinstance(index_arguments, IndexArgsHNSW)
+                and method != IndexMethod.hnsw
+            ) or (
+                isinstance(index_arguments, IndexArgsIVFFlat)
+                and method != IndexMethod.ivfflat
+            ):
+                raise ArgError(
+                    f"{index_arguments.__class__.__name__} build parameters were supplied but {method} index was specified."
+                )
+
+        if method == IndexMethod.auto:
+            if self.client._supports_hnsw():
+                method = IndexMethod.hnsw
+            else:
+                method = IndexMethod.ivfflat
+
+        if method == IndexMethod.hnsw and not self.client._supports_hnsw():
+            raise ArgError(
+                "HNSW Unavailable. Upgrade your pgvector installation to > 0.5.0 to enable HNSW support"
+            )
+
+        ops = INDEX_MEASURE_TO_OPS.get(measure)
+        if ops is None:
+            raise ArgError("Unknown index measure")
+
+        unique_string = str(uuid.uuid4()).replace("-", "_")[0:7]
+
+        with self.client.Session() as sess:
+            with sess.begin():
+                if self.index is not None:
+                    if replace:
+                        sess.execute(text(f'drop index vecs."{self.index}";'))
+                        self._index = None
+                    else:
+                        raise ArgError("replace is set to False but an index exists")
+
+                if method == IndexMethod.ivfflat:
+                    if not index_arguments:
+                        n_records: int = sess.execute(func.count(self.table.c.id)).scalar()  # type: ignore
+
+                        n_lists = (
+                            int(max(n_records / 1000, 30))
+                            if n_records < 1_000_000
+                            else int(math.sqrt(n_records))
+                        )
+                    else:
+                        # The following mypy error is ignored because mypy
+                        # complains that `index_arguments` is typed as a union
+                        # of IndexArgsIVFFlat and IndexArgsHNSW types,
+                        # which both don't necessarily contain the `n_lists`
+                        # parameter, however we have validated that the
+                        # correct type is being used above.
+                        n_lists = index_arguments.n_lists  # type: ignore
+
+                    sess.execute(
+                        text(
+                            f"""
+                            create index ix_{ops}_ivfflat_nl{n_lists}_{unique_string}
+                              on vecs."{self.table.name}"
+                              using ivfflat (vec {ops}) with (lists={n_lists})
+                            """
+                        )
+                    )
+
+                if method == IndexMethod.hnsw:
+                    if not index_arguments:
+                        index_arguments = IndexArgsHNSW()
+
+                    # See above for explanation of why the following lines
+                    # are ignored
+                    m = index_arguments.m  # type: ignore
+                    ef_construction = index_arguments.ef_construction  # type: ignore
+
+                    sess.execute(
+                        text(
+                            f"""
+                            create index ix_{ops}_hnsw_m{m}_efc{ef_construction}_{unique_string}
+                              on vecs."{self.table.name}"
+                              using hnsw (vec {ops}) WITH (m={m}, ef_construction={ef_construction});
+                            """
+                        )
+                    )
+
+        return None
+
+
+def build_filters(json_col: Column, filters: Dict):
+    """
+    PRIVATE
+
+    Builds filters for SQL query based on provided dictionary.
+
+    Args:
+        json_col (Column): The column in the database table.
+        filters (Dict): The dictionary specifying filter conditions.
+
+    Raises:
+        FilterError: If filter conditions are not correctly formatted.
+
+    Returns:
+        The filter clause for the SQL query.
+    """
+
+    if not isinstance(filters, dict):
+        raise FilterError("filters must be a dict")
+
+    if len(filters) > 1:
+        raise FilterError("max 1 entry per filter")
+
+    for key, value in filters.items():
+        if not isinstance(key, str):
+            raise FilterError("*filters* keys must be strings")
+
+        if key in ("$and", "$or"):
+            if not isinstance(value, list):
+                raise FilterError(
+                    "$and/$or filters must have associated list of conditions"
+                )
+
+            if key == "$and":
+                return and_(*[build_filters(json_col, subcond) for subcond in value])
+
+            if key == "$or":
+                return or_(*[build_filters(json_col, subcond) for subcond in value])
+
+            raise Unreachable()
+
+        if isinstance(value, dict):
+            if len(value) > 1:
+                raise FilterError("only one operator permitted")
+            for operator, clause in value.items():
+                if operator not in (
+                    "$eq",
+                    "$ne",
+                    "$lt",
+                    "$lte",
+                    "$gt",
+                    "$gte",
+                    "$in",
+                    "$contains",
+                ):
+                    raise FilterError("unknown operator")
+
+                # equality of singular values can take advantage of the metadata index
+                # using containment operator. Containment can not be used to test equality
+                # of lists or dicts so we restrict to single values with a __len__ check.
+                if operator == "$eq" and not hasattr(clause, "__len__"):
+                    contains_value = cast({key: clause}, postgresql.JSONB)
+                    return json_col.op("@>")(contains_value)
+
+                if operator == "$in":
+                    if not isinstance(clause, list):
+                        raise FilterError("argument to $in filter must be a list")
+
+                    for elem in clause:
+                        if not isinstance(elem, (int, str, float)):
+                            raise FilterError(
+                                "argument to $in filter must be a list of scalars"
+                            )
+
+                    # cast the array of scalars to a postgres array of jsonb so we can
+                    # directly compare json types in the query
+                    contains_value = [cast(elem, postgresql.JSONB) for elem in clause]
+                    return json_col.op("->")(key).in_(contains_value)
+
+                matches_value = cast(clause, postgresql.JSONB)
+
+                # @> in Postgres is heavily overloaded.
+                # By default, it will return True for
+                #
+                # scalar in array
+                #   '[1, 2, 3]'::jsonb @> '1'::jsonb -- true#
+                # equality:
+                #   '1'::jsonb @> '1'::jsonb -- true
+                # key value pair in object
+                #   '{"a": 1, "b": 2}'::jsonb @> '{"a": 1}'::jsonb -- true
+                #
+                # At this time we only want to allow "scalar in array" so
+                # we assert that the clause is a scalar and the target metadata
+                # is an array
+                if operator == "$contains":
+                    if not isinstance(clause, (int, str, float)):
+                        raise FilterError(
+                            "argument to $contains filter must be a scalar"
+                        )
+
+                    return and_(
+                        json_col.op("->")(key).contains(matches_value),
+                        func.jsonb_typeof(json_col.op("->")(key)) == "array",
+                    )
+
+                # handles non-singular values
+                if operator == "$eq":
+                    return json_col.op("->")(key) == matches_value
+
+                elif operator == "$ne":
+                    return json_col.op("->")(key) != matches_value
+
+                elif operator == "$lt":
+                    return json_col.op("->")(key) < matches_value
+
+                elif operator == "$lte":
+                    return json_col.op("->")(key) <= matches_value
+
+                elif operator == "$gt":
+                    return json_col.op("->")(key) > matches_value
+
+                elif operator == "$gte":
+                    return json_col.op("->")(key) >= matches_value
+
+                else:
+                    raise Unreachable()
+
+
+def build_table(name: str, meta: MetaData, dimension: int) -> Table:
+    """
+    PRIVATE
+
+    Builds a SQLAlchemy model underpinning a `vecs.Collection`.
+
+    Args:
+        name (str): The name of the table.
+        meta (MetaData): MetaData instance associated with the SQL database.
+        dimension: The dimension of the vectors in the collection.
+
+    Returns:
+        Table: The constructed SQL table.
+    """
+    return Table(
+        name,
+        meta,
+        Column("id", String, primary_key=True),
+        Column("vec", Vector(dimension), nullable=False),
+        Column(
+            "metadata",
+            postgresql.JSONB,
+            server_default=text("'{}'::jsonb"),
+            nullable=False,
+        ),
+        extend_existing=True,
+    )