Results of 1 - 9 of about 9 for Pointer (0.005 sec.)
- Vectors 12942
- Vectors represent a horizontal slice of a column. They hold a number of values of a specific type, similar to an array. Vectors are the core data representation used in DuckDB. Vectors are typically stored within data chunks . The vector an
...uckdb_validity_row_is_valid can be used to check whether or not a value is NULL . The duckdb_vector_get_validity returns a pointer to the validity mask. Note that if all values in a vector are valid, this function might return nullptr in which case the...ed as a duckdb_string_t . This is a special struct that stores the string inline (if it is short, i.e., <= 12 bytes ) or a pointer to the string data if it is longer than 12 bytes. typedef struct { union { struct { uint32_t length; char prefix[4]; char...*ptr; } pointer; struct { uint32_t length; char inlined[12]; } inlined; } value; } duckdb_string_t; The length can either be accessed dire... - https://man.mtool.work/duckdb/2.0/clients/c/vector.html
- JSON Overview 10874
- DuckDB supports SQL functions that are useful for reading values from existing JSON and creating new JSON data. JSON is supported with the json extension which is shipped with most DuckDB distributions and is auto-loaded on first use. If yo
...ry efficient format for tabular data, it is very commonly used, especially as a data interchange format. JSONPath and JSON Pointer Syntax DuckDB implements multiple interfaces for JSON extraction: JSONPath and JSON Pointer . Both of them work with the a...syntax because SQL is readily available for any further transformations. It's best to pick either the JSONPath or the JSON Pointer syntax and use it in your entire application. Indexing Warning Following PostgreSQL's conventions , DuckDB uses 1-based in... - https://man.mtool.work/duckdb/2.0/data/json/overview.html
- Complete API 9436
- 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
...e false. duckdb_query Executes a SQL query within a connection and stores the full (materialized) result in the out_result pointer. If the query fails to execute, DuckDBError is returned and the error message can be retrieved by calling duckdb_result_er...ckdb_free . Syntax void * duckdb_malloc ( size_t size ); Parameters size : The number of bytes to allocate. Return Value A pointer to the allocated memory region. duckdb_free Free a value returned from duckdb_malloc , duckdb_value_varchar , duckdb_value...tring_t string ); Parameters string : The string to get the length of. Return Value The length. duckdb_string_t_data Get a pointer to the string data of a string_t Syntax const char * duckdb_string_t_data ( duckdb_string_t * string ); Parameters string... - https://man.mtool.work/duckdb/2.0/clients/c/api.html
- Query 8807
- The duckdb_query method allows SQL queries to be run in DuckDB from C. This method takes two parameters, a (null-terminated) SQL query string and a duckdb_result result pointer. The result pointer may be NULL if the application is not inter
...esult ); duckdb_query Executes a SQL query within a connection and stores the full (materialized) result in the out_result pointer. If the query fails to execute, DuckDBError is returned and the error message can be retrieved by calling duckdb_result_er... - https://man.mtool.work/duckdb/2.0/clients/c/query.html
- Execution Format 8807
- Vector is the container format used to store in-memory data during execution. DataChunk is a collection of Vectors, used for instance to represent a column list in a PhysicalProjection operator. Data Flow DuckDB uses a vectorized query exec
...rings, we make use of our string_t class. struct string_t { union { struct { uint32_t length; char prefix[4]; char *ptr; } pointer; struct { uint32_t length; char inlined[12]; } inlined; } value; }; Short strings ( <= 12 bytes ) are inlined into the str...ucture, while larger strings are stored with a pointer to the data in the auxiliary string buffer. The length is used throughout the functions to avoid having to call strlen and...having to continuously check for null-pointers. The prefix is used for comparisons as an early out (when the prefix does not match, we know the strings are not equal an... - https://man.mtool.work/duckdb/2.0/internals/vector.html
- ODBC 101: A Duck Themed Guide to ODBC 7998
- What is ODBC? ODBC which stands for Open Database Connectivity, is a standard that allows different programs to talk to different databases including, of course, DuckDB. This makes it easier to build programs that work with many different d
...e about ODBC. General Concepts Handles Connecting Error Handling and Diagnostics Buffers and Binding Handles A handle is a pointer to a specific ODBC object which is used to interact with the database. There are several different types of handles, each...scriptor handle. Handles are allocated using the SQLAllocHandle which takes as input the type of handle to allocate, and a pointer to the handle, the driver then creates a new handle of the specified type, which it returns to the application. The DuckDB... - https://man.mtool.work/duckdb/2.0/guides/odbc/general.html
- Data Chunks 7693
- Data chunks represent a horizontal slice of a table. They hold a number of vectors , that can each hold up to the VECTOR_SIZE rows. The vector size can be obtained through the duckdb_vector_size function and is configurable, but is usually
...lling this method, you must call duckdb_vector_get_validity and duckdb_vector_get_data to obtain current data and validity pointers Syntax void duckdb_data_chunk_reset ( duckdb_data_chunk chunk ); Parameters chunk : The data chunk to reset. duckdb_data_...s in the data chunk duckdb_data_chunk_get_vector Retrieves the vector at the specified column index in the data chunk. The pointer to the vector is valid for as long as the chunk is alive. It does NOT need to be destroyed. Syntax duckdb_vector duckdb_da... - https://man.mtool.work/duckdb/2.0/clients/c/data_chunk.html
- Table Functions 7208
- The table function API can be used to define a table function that can then be called from within DuckDB in the FROM clause of a query. API Reference Overview duckdb_table_function duckdb_create_table_function (); void duckdb_destroy_table_
...nection con , duckdb_table_function function ); Parameters con : The connection to register it in. function : The function pointer Return Value Whether or not the registration was successful. duckdb_bind_get_extra_info Retrieves the extra info of the fu... - https://man.mtool.work/duckdb/2.0/clients/c/table_functions.html
- JSON Processing Functions 7046
- JSON Extraction Functions There are two extraction functions, which have their respective operators. The operators can only be used if the string is stored as the JSON logical type. These functions support the same two location notations as
...produce an error when invalid JSON is supplied. We support two kinds of notations to describe locations within JSON: JSON Pointer and JSONPath. Function Description json_array_length(json[, path]) Return the number of elements in the JSON array json ,...sult will be LIST of types. json_valid(json) Return whether json is valid JSON. json(json) Parse and minify json . The JSONPointer syntax separates each field with a / . For example, to extract the first element of the array with key duck , you can do:... - https://man.mtool.work/duckdb/2.0/data/json/json_functions.html
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