Results of 1 - 10 of about 25 for Replacement (0.003 sec.)
- Replacement Scans 16007
- The replacement scan API can be used to register a callback that is called when a table is read that does not exist in the catalog. For example, when a query such as SELECT * FROM my_table is executed and my_table does not exist, the replacement
...ement scan callback will be called with my_table as parameter. The replacement scan can then insert a table function with a specific parameter to replace the read of the table. API Reference Overview v...oid duckdb_add_replacement_scan ( duckdb_database db , duckdb_replacement_callback_t replacement , void * extra_data , duckdb_delete_callback_t delet...e_callback ); void duckdb_replacement_scan_set_function_name ( duckdb_replacement_scan_info info , const char * function_name ); void duckdb_replacement_scan_ad... - https://man.mtool.work/duckdb/2.0/clients/c/replacement_scans.html
- Glossary of Terms 9697
- This page contains a glossary of a few common terms used in DuckDB. Terms In-Process Database Management System The DBMS runs in the client application's process instead of running as a separate process, which is common in the traditional c
...tem” should be avoided, as it can be confused with DBMSs targeting embedded systems (which run on e.g., microcontrollers). Replacement Scan In DuckDB, replacement scans are used when a table name used by a query does not exist in the catalog. These scans ca...n substitute another data source instead of the table. Using replacement scans allows DuckDB to, e.g., seamlessly read Pandas DataFrames or read input data from remote sources without explicitly...invoking the functions that perform this (e.g., reading Parquet files from https ). For details, see the C API – Replacement Scans page . Extension DuckDB has a flexible extension mechanism that allows for dynamically loading extensions. These may... - https://man.mtool.work/duckdb/2.0/guides/glossary.html
- Write User Defined Functions 9132
- Overview The Go client can register user-defined functions written in Go: scalar functions that map input rows to a single output value, and table functions that produce a set of rows. It can also register a replacement scan that rewrites a
...ed table name into a query. Scalar and table functions are registered on a connection checked out with db.Conn() , while a replacement scan is registered on a Connector ; in each case the function is then callable from SQL like any built-in. The sections be...e so each thread can claim and emit its own range of rows. The client's table_udf_parallel example shows the full pattern. Replacement Scans A replacement scan intercepts a query that references a table name DuckDB cannot resolve and rewrites it into a tabl...e function call. Register one on a Connector with duckdb.RegisterReplacementScan() , passing a callback of type duckdb.ReplacementScanCallback . The callback receives the unresolved table name and re... - https://man.mtool.work/duckdb/2.0/clients/go/functions.html
- Regular Expressions 8800
- DuckDB offers pattern matching operators ( LIKE , SIMILAR TO , GLOB ), as well as support for regular expressions via functions. Regular Expression Syntax DuckDB uses the RE2 library as its regular expression engine. For the regular express
...pattern[, options]) Returns true if string contains the regexp pattern , false otherwise. regexp_replace(string, pattern, replacement[, options]) If string contains the regexp pattern , replaces the matching part with replacement . By default, only the fir...options can be set. | | Example | regexp_matches('anabanana', '(an)*') | | Result | true | regexp_replace(string, pattern, replacement[, options]) | Description | If string contains the regexp pattern , replaces the matching part with replacement . By defau...exp_replace The regexp_replace function can be used to replace the part of a string that matches the regexp pattern with a replacement string. The notation \d (where d is a number indicating the group) can be used to refer to groups captured in the regular... - https://man.mtool.work/duckdb/2.0/sql/functions/regular_expressions.html
- Data Ingestion 8418
- This page contains examples for data ingestion to Python using DuckDB. First, import the DuckDB package: import duckdb Then, proceed with any of the following sections. CSV Files CSV files can be read using the read_csv function, called eit
...o look in the functions that called it, set python_scan_all_frames to true . Accessing these variables is made possible by replacement scans . To disable replacement scans entirely, use: SET python_enable_replacements = false; The precedence of objects with...the same name is as follows: Objects explicitly registered via register() Native DuckDB tables and views Replacement scans DuckDB supports querying multiple types of Apache Arrow objects including tables , record batches, arrays and chunke...mplements the Arrow PyCapsule interface through an __arrow_c_stream__ method. Such objects can be queried directly through replacement scans and passed to duckdb.from_arrow() : import duckdb import pyarrow as pa class MyArrowStream: def __init__(self, table... - https://man.mtool.work/duckdb/2.0/clients/python/data_ingestion.html
- Text Functions 8269
- Text Functions and Operators This section describes functions and operators for examining and manipulating STRING values . Function Description string[index] Extracts a single character using a (1-based) index . string[begin:end] Extracts a
...if string contains the regex , false otherwise. A set of optional regex options can be set. regexp_replace(string, regex, replacement[, options]) If string contains the regex , replaces the matching part with replacement . A set of optional regex options c...x options can be set. | | Example | regexp_matches('anabanana', '(an)*') | | Result | true | regexp_replace(string, regex, replacement[, options]) | Description | If string contains the regex , replaces the matching part with replacement . A set of optional...verlay New The overlay function was introduced in DuckDB 2.0. The overlay function replaces a substring of a string with a replacement string. It supports the SQL-standard syntax overlay(⟨string⟩ PLACING ⟨replacement⟩ FROM ⟨start⟩ [FOR ⟨count⟩]) , where sta... - https://man.mtool.work/duckdb/2.0/sql/functions/text.html
- HTTP Parquet Import 8036
- To load a Parquet file over HTTP(S), the httpfs extension is required. This can be installed using the INSTALL SQL command. This only needs to be run once. INSTALL httpfs; To load the httpfs extension for usage, use the LOAD SQL command: LO
...ttps://duckdb.org/data/prices.parquet'); Moreover, the read_parquet function itself can also be omitted thanks to DuckDB's replacement scan mechanism : SELECT * FROM 'https://duckdb.org/data/holdings.parquet';... - https://man.mtool.work/duckdb/2.0/guides/network_cloud_storage/http_import.html
- SQL on Pandas 8036
- Pandas DataFrames stored in local variables can be queried as if they are regular tables within DuckDB. import duckdb import pandas # Create a Pandas dataframe my_df = pandas.DataFrame.from_dict({'a': [42]}) # query the Pandas DataFrame "my
...duckdb.sql("SELECT * FROM my_df").df() The seamless integration of Pandas DataFrames into DuckDB SQL queries is allowed by replacement scans , which replace instances of accessing the my_df table (which does not exist in DuckDB) with a table function that r... - https://man.mtool.work/duckdb/2.0/guides/python/sql_on_pandas.html
- Complete API 7987
- This page contains the reference for DuckDB's C API. The reference contains several deprecation notices. These concern methods whose long-term availability is not guaranteed as they may be removed in the future. That said, DuckDB's develope
...nit_data ( duckdb_function_info info ); void duckdb_function_set_error ( duckdb_function_info info , const char * error ); Replacement Scans void duckdb_add_replacement_scan ( duckdb_database db , duckdb_replacement_callback_t replacement , void * extra_dat...a , duckdb_delete_callback_t delete_callback ); void duckdb_replacement_scan_set_function_name ( duckdb_replacement_scan_info info , const char * function_name ); void duckdb_replacement_scan_ad...d_parameter ( duckdb_replacement_scan_info info , duckdb_value parameter ); void duckdb_replacement_scan_set_error ( duckdb_replacement_scan_info info , co... - https://man.mtool.work/duckdb/2.0/clients/c/api.html
- DuckDB Repositories 7987
- Several components of DuckDB are maintained in separate repositories. Main Repositories duckdb : core DuckDB project duckdb-web : documentation and blog duckdb-quack : Quack remote protocol Clients duckdb-go : Go client duckdb-java : Java (
...kdb-r : R client duckdb-rs : Rust client duckdb-swift : Swift client duckdb-wasm : WebAssembly client duckplyr : a drop-in replacement for dplyr in R DuckDB.jl : Julia client Connectors dbt-duckdb : dbt duckdb-mysql : MySQL connector duckdb-postgres : Postg... - https://man.mtool.work/duckdb/2.0/dev/repositories.html
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