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Data Frame Source

Source: R/DataSource.R
DataFrameSource.Rd

A DataSource implementation that wraps a data frame using DuckDB for SQL query execution.

Details

This class creates an in-memory DuckDB connection and registers the provided data frame as a table. All SQL queries are executed against this DuckDB table.

Super class

querychat::DataSource -> DataFrameSource

Methods

Public methods

Method new()

Create a new DataFrameSource

Usage

DataFrameSource$new(df, table_name)

Arguments

df

A data frame.

table_name

Name to use for the table in SQL queries. Must be a valid table name (start with letter, contain only letters, numbers, and underscores)

Returns

A new DataFrameSource object

Examples

\dontrun{
source <- DataFrameSource$new(iris, "iris")
}

Method get_db_type()

Get the database type

Usage

DataFrameSource$get_db_type()

Returns

The string "DuckDB"

Method get_schema()

Get schema information for the data frame

Usage

DataFrameSource$get_schema(categorical_threshold = 20)

Arguments

categorical_threshold

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

Returns

A string describing the schema

Method execute_query()

Execute a SQL query

Usage

DataFrameSource$execute_query(query)

Arguments

query

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

Returns

A data frame with query results

Method test_query()

Test a SQL query by fetching only one row

Usage

DataFrameSource$test_query(query)

Arguments

query

SQL query string

Returns

A data frame with one row of results

Method get_data()

Get all data from the table

Usage

DataFrameSource$get_data()

Returns

A data frame containing all data

Method cleanup()

Close the DuckDB connection

Usage

DataFrameSource$cleanup()

Returns

NULL (invisibly)

Method clone()

The objects of this class are cloneable with this method.

Usage

DataFrameSource$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

if (FALSE) { # \dontrun{
# Create a data frame source
df_source <- DataFrameSource$new(mtcars, "mtcars")

# Get database type
df_source$get_db_type()  # Returns "DuckDB"

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

# Clean up when done
df_source$cleanup()
} # }

## ------------------------------------------------
## Method `DataFrameSource$new`
## ------------------------------------------------

if (FALSE) { # \dontrun{
source <- DataFrameSource$new(iris, "iris")
} # }