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The completion table can be +used to help implement tab-completion, for example. + +</p><h1 id="details"><span>2. </span>Details</h1> + +<p>The designed query interface is: + +</p><div class="codeblock"><pre>SELECT DISTINCT candidate COLLATE nocase + FROM completion($prefix, $wholeline) + ORDER BY 1; +</pre></div> + +<p>The query above will return suggestions for the whole input word that +begins with $prefix. The $wholeline parameter is all text from the beginning +of the line up to the insertion point. The $wholeline parameter is used +for context. + +</p><p>The $prefix parameter may be NULL, in which case the prefix is deduced +from $wholeline. Or, the $wholeline parameter may be NULL or omitted if +context information is unavailable or if context-aware completion is not +desired. + +</p><p>The completion table might return the same candidate more than once, and +it will return candidates in an arbitrary order. The DISTINCT keyword and +the ORDER BY in the sample query above are added to make the answers unique +and in lexicographical order. + +</p><h2 id="example_usage"><span>2.1. </span>Example Usage</h2> + +<p>The completion table is used to implement tab-completion in the +<a href="cli.html">command-line shell</a> in conjunction with either the readline or linenoise +input line editing packages for unix. See the +<a href="https://sqlite.org/src/file/src/shell.c.in">https://sqlite.org/src/file/src/shell.c.in</a> source file for example +code. Search for "FROM completion" to find the relevant code sections. + +</p><p>Because the completion table is built into the command-line shell in order +to provide for tab-completions, you can run test queries against the +completion table directly in the command-line shell. Simply type a +query such as the example shown above, filling in appropriate values +for $prefix and $wholeline, and observe the output. + +</p><h1 id="limitations"><span>3. </span>Limitations</h1> + +<p>The completion table is designed for interactive use. It will return +answers at a speed appropriate for human typing. No effort is made to +be unusually efficient, so long as the response time is nearly instantaneous +in a user interface. + +</p><p>As of this writing (2017-07-13), the completion virtual table only +looks for SQL keywords, and schema, table, and column names. The +context contained in $wholeline is completely ignored. Future enhancements +will try to return new completions taken from function and pragma names +and other sources, as well as consider more context. The completion +table should be considered a work-in-progress. +</p><p align="center"><small><i>This page last modified on <a href="https://sqlite.org/docsrc/honeypot" id="mtimelink" data-href="https://sqlite.org/docsrc/finfo/pages/completion.in?m=887445dcd19c18f0d">2017-07-14 03:53:46</a> UTC </small></i></p> + |