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Feature engineering is now the overview plus one page per operation: add a computed column, refresh a column, refresh a materialized view. Computed columns covered declaring and filling on one page, which are separate decisions with separate failure modes. Functions move to Management, where the other catalog objects are, and absorb the environment-mismatch guidance from the Enterprise page -- a symptom table worth having beside the parameters that cause it. The Enterprise feature-engineering page is merged into the overview. Two of its claims were stale: create_materialized_view is implemented for db:// connections in remote/db.py, so views are not local-only, and the tier is Enterprise rather than 'Cloud and Enterprise'. The REST reference leaves the sidebar. Mintlify only generates per-endpoint pages from a navigation group -- hidden, dropdowns, global anchors and a top-level openapi key were all tried -- so removing the group removes those pages. The overview survives as an unlisted page, linked from SDKs & SQL, and the spec still ships for anything that wants to read it directly.
195 lines
6.2 KiB
Plaintext
195 lines
6.2 KiB
Plaintext
---
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title: "Database"
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sidebarTitle: "Database"
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description: "Connecting to LanceDB: the URI forms, their options, and what each one changes."
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icon: database
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keywords: ["connect", "database", "uri", "api key", "storage options", "consistency"]
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---
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A database is the root of a [catalog](/basics/catalog). A connection opens
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exactly one, and every other object is reached through it.
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Connecting is the one decision that reaches furthest: the URI you pass decides
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where queries execute, which features exist, and what a table handle actually
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is.
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## The three URI forms {#uris}
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<CodeGroup>
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```python Python icon="python"
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import lancedb
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db = lancedb.connect("./.lancedb") # local directory
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db = lancedb.connect("s3://bucket/path") # object storage
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db = lancedb.connect("db://my-database", api_key="...") # a deployment
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```
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```typescript TypeScript icon="square-js"
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import * as lancedb from "@lancedb/lancedb";
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const db = await lancedb.connect("./.lancedb");
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const db = await lancedb.connect("s3://bucket/path");
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const db = await lancedb.connect("db://my-database", { apiKey: "..." });
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```
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</CodeGroup>
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The first two are **embedded**: your process opens Lance tables directly from
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storage and does the work itself. The third talks to a **deployment**.
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| | Embedded | Deployment |
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| --- | --- | --- |
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| Where queries run | in your process | on the server |
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| Table handle | `LanceTable` | `RemoteTable` |
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| [SQL](/basics/apis) | -- | yes |
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| Server-side [jobs](/basics/jobs) | -- | yes |
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| [Functions](/management/function) | -- | yes |
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| [Authorization](/governance/authorization) | storage permissions | granted per object |
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Both handles expose the same table API -- create, open, mutate, query -- so
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application code moves between them by changing the URI. What differs is where
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resolution and execution happen, and therefore which operations exist at all.
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## Connecting to a deployment {#deployment}
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<Badge color="red">Enterprise</Badge>
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<CodeGroup>
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```python Python icon="python"
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db = lancedb.connect(
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"db://my-database",
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api_key="...",
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region="us-east-1",
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)
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```
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```typescript TypeScript icon="square-js"
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const db = await lancedb.connect("db://my-database", {
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apiKey: "...",
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region: "us-east-1",
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});
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```
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</CodeGroup>
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| Option | Meaning |
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| --- | --- |
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| `api_key` / `apiKey` | authenticates the connection -- see [Authentication](/enterprise/authentication) |
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| `region` | which region hosts the database. Defaults to `us-east-1` |
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| `host_override` / `hostOverride` | point at a specific endpoint instead of the regional one |
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| `sql_host_override` | the same, for the [SQL endpoint](/search/sql). Python only |
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| `client_config` / `clientConfig` | retries, timeouts, and connection pooling |
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An API key belongs in the environment, not in source. `region` is easy to get
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wrong silently -- the default is `us-east-1` whether or not that is where your
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database lives, and a wrong region fails as a connection error rather than a
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helpful one.
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## Storage options {#storage-options}
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`storage_options` configures the underlying object store -- credentials,
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endpoints, and defaults for tables created through this connection:
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<CodeGroup>
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```python Python icon="python"
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db = lancedb.connect(
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"s3://bucket/path",
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storage_options={"new_table_enable_stable_row_ids": "true"},
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)
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```
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```typescript TypeScript icon="square-js"
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const db = await lancedb.connect("s3://bucket/path", {
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storageOptions: { new_table_enable_stable_row_ids: "true" },
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});
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```
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</CodeGroup>
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<Warning>
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`new_table_enable_stable_row_ids` is worth setting deliberately. Stable row ids
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cannot be enabled after a table exists, and a
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[materialized view](/feature-engineering/materialized-views) requires its source
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to have them. A table created without them cannot later become a view's source
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without being recreated.
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</Warning>
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See [Storage](/storage) for the full set, including per-cloud credentials.
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## Read consistency {#consistency}
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`read_consistency_interval` controls how often a connection checks for versions
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committed by other writers.
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<CodeGroup>
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```python Python icon="python"
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from datetime import timedelta
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db = lancedb.connect(uri, read_consistency_interval=timedelta(seconds=5))
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```
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```typescript TypeScript icon="square-js"
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const db = await lancedb.connect(uri, { readConsistencyInterval: 5 });
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```
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</CodeGroup>
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The default reads a snapshot taken when the table was opened, so a long-lived
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connection **will not see other processes' writes** until it reopens the table.
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That is the right default for a batch job and the wrong one for a service.
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Set it when several processes write the same table and readers must observe
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those writes. The cost is a metadata check on that interval. See
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[Consistency](/tables/consistency).
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## Database-level operations {#operations}
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| | Python | TypeScript | SQL |
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| --- | --- | --- | --- |
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| list tables | `table_names`, `list_tables` | `tableNames`, `listTables` | `SHOW TABLES` |
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| the URI it opened | `uri` | `display()` | -- |
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| drop every table | `drop_all_tables` | `dropAllTables` | -- |
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| drop the database | `drop_database` | -- | -- |
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| close | -- | `close`, `isOpen` | -- |
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<CodeGroup>
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```python Python icon="python"
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db.table_names()
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tbl = db.open_table("documents")
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db.drop_table("documents")
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```
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```typescript TypeScript icon="square-js"
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await db.tableNames();
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const tbl = await db.openTable("documents");
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await db.dropTable("documents");
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```
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```sql SQL
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SHOW TABLES;
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DROP TABLE documents;
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```
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</CodeGroup>
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Each takes a `namespace_path` to act inside a [namespace](/namespaces) rather
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than at the root.
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<Warning>
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`drop_database()` removes every table in the database. There is no confirmation
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and no undo -- table [versioning](/tables/versioning) does not survive the table
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being dropped.
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</Warning>
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## Async connections {#async}
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`connect_async` returns an `AsyncConnection` with the same surface as
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coroutines. The TypeScript SDK is async throughout, so its `connect` already is
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one.
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```python
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db = await lancedb.connect_async("db://my-database", api_key="...")
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tbl = await db.open_table("documents")
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```
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This is a different axis from the `_async` operations that return a
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[job](/basics/jobs): `connect_async` is about not blocking your event loop,
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while `create_index_async` is about work that outlives the call.
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