DBI Source

A DataSource implementation for DBI database connections (SQLite, PostgreSQL, MySQL, etc.). This class wraps a DBI connection and provides SQL query execution against a single table in the database.

Super class

DataSource -> DBISource

Active bindings

conn

The DBI connection backing this source (read-only).

Methods

Public methods

• DBISource$new()

• DBISource$get_db_type()

• DBISource$get_schema()

• DBISource$get_schema_result()

• DBISource$get_semantic_views_description()

• DBISource$execute_query()

• DBISource$test_query()

• DBISource$get_data()

• DBISource$cleanup()

• DBISource$clone()

Inherited methods

• DataSource$get_data_description()

---

DBISource$new()

Create a new DBISource

Usage

DBISource$new(conn, table_name)

Arguments

conn

A DBI connection object

table_name

Name of the table in the database. Can be a character string or a DBI::Id() object for tables in catalogs/schemas

Returns

A new DBISource object

---

DBISource$get_db_type()

Get the database type

Usage

DBISource$get_db_type()

Returns

A string identifying the database type

---

DBISource$get_schema()

Get schema information for the database table

Usage

DBISource$get_schema(categorical_threshold = 20, table_spec = NULL)

Arguments

categorical_threshold

Maximum number of unique values for a text column to be considered categorical (default: 20)

Returns

A string describing the schema

---

DBISource$get_schema_result()

Usage

DBISource$get_schema_result(categorical_threshold = 20, table_spec = NULL)

---

DBISource$get_semantic_views_description()

Get information about semantic views (if any) for the system prompt.

Usage

DBISource$get_semantic_views_description()

Returns

A string with semantic view information, or empty string if none

---

DBISource$execute_query()

Execute a SQL query

Usage

DBISource$execute_query(query)

Arguments

query

SQL query string. If NULL or empty, returns all data

Returns

A data frame with query results

---

DBISource$test_query()

Test a SQL query by fetching only one row

Usage

DBISource$test_query(query, require_all_columns = FALSE)

Arguments

query

SQL query string

require_all_columns

If TRUE, validates that the result includes all original table columns (default: FALSE)

Returns

A data frame with one row of results

---

DBISource$get_data()

Get all data from the table

Usage

DBISource$get_data()

Returns

A data frame containing all data

---

DBISource$cleanup()

No-op: the DBI connection is owned by the caller. Disconnect it yourself with DBI::dbDisconnect() when your application shuts down.

Usage

DBISource$cleanup()

Returns

NULL (invisibly)

---

DBISource$clone()

The objects of this class are cloneable with this method.

Usage

DBISource$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# Connect to a database
con <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
DBI::dbWriteTable(con, "mtcars", mtcars)

# Create a DBI source
db_source <- DBISource$new(con, "mtcars")

# Get database type
db_source$get_db_type()  # Returns "SQLite"
#> [1] "SQLite"

# Execute a query
result <- db_source$execute_query("SELECT * FROM mtcars WHERE mpg > 25")

# cleanup() is a no-op: you own `con`, so disconnect it yourself
db_source$cleanup()
DBI::dbDisconnect(con)