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61 lines
2.9 KiB
Markdown
61 lines
2.9 KiB
Markdown
## Miscellaneous Extensions
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This folder contains a collection of smaller loadable extensions.
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See <https://www.sqlite.org/loadext.html> for instructions on how
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to compile and use loadable extensions.
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Each extension in this folder is implemented in a single file of C code.
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Each source file contains a description in its header comment. See the
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header comments for details about each extension. Additional notes are
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as follows:
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* **carray.c** — This module implements the
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[carray](https://www.sqlite.org/carray.html) table-valued function.
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It is a good example of how to go about implementing a custom
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[table-valued function](https://www.sqlite.org/vtab.html#tabfunc2).
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* **csv.c** — A [virtual table](https://sqlite.org/vtab.html)
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for reading
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[Comma-Separated-Value (CSV) files](https://en.wikipedia.org/wiki/Comma-separated_values).
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* **dbdump.c** — This is not actually a loadable extension, but
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rather a library that implements an approximate equivalent to the
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".dump" command of the
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[command-line shell](https://www.sqlite.org/cli.html).
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* **json1.c** — Various SQL functions and table-valued functions
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for processing JSON. This extension is already built into the
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[SQLite amalgamation](https://sqlite.org/amalgamation.html). See
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<https://sqlite.org/json1.html> for additional information.
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* **memvfs.c** — This file implements a custom
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[VFS](https://www.sqlite.org/vfs.html) that stores an entire database
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file in a single block of RAM. It serves as a good example of how
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to implement a simple custom VFS.
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* **rot13.c** — This file implements the very simple rot13()
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substitution function. This file makes a good template for implementing
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new custom SQL functions for SQLite.
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* **series.c** — This is an implementation of the
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"generate_series" [virtual table](https://www.sqlite.org/vtab.html).
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It can make a good template for new custom virtual table implementations.
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* **shathree.c** — An implementation of the sha3() and
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sha3_query() SQL functions. The file is named "shathree.c" instead
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of "sha3.c" because the default entry point names in SQLite are based
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on the source filename with digits removed, so if we used the name
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"sha3.c" then the entry point would conflict with the prior "sha1.c"
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extension.
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* **unionvtab.c** — Implementation of the unionvtab and
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[swarmvtab](https://sqlite.org/swarmvtab.html) virtual tables.
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These virtual tables allow a single
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large table to be spread out across multiple database files. In the
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case of swarmvtab, the individual database files can be attached on
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demand.
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* **zipfile.c** — A [virtual table](https://sqlite.org/vtab.html)
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that can read and write a
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[ZIP archive](https://en.wikipedia.org/wiki/Zip_%28file_format%29).
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