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Namespace and Table were the only objects behind a nested group. Both are now a single page like Database, Materialized view, View and Function, so Manage is a flat list of the things a catalog holds. Namespace merges its two pages, which were a concept page and a usage page for the same object. Table is a new page. The old tables/index was a 672-line basic-usage tutorial whose every section had acquired a better home during the restructure -- connecting, ingesting, searching, filtering, adding and dropping columns -- to the point that its own Next steps cards pointed at the pages that superseded it. It is replaced by a table object page: what a table carries, create, open, list, rename, clone, drop, and links out. Schema evolution, versioning and branching stay as siblings rather than folding in. Merging them would have made one 1,800-line page, which is not what the other object pages look like.
195 lines
6.3 KiB
Plaintext
195 lines
6.3 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](/management/namespace) 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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