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diff --git a/www/csv.html b/www/csv.html new file mode 100644 index 0000000..1b87759 --- /dev/null +++ b/www/csv.html @@ -0,0 +1,240 @@ +<!DOCTYPE html> +<html><head> +<meta name="viewport" content="width=device-width, initial-scale=1.0"> +<meta http-equiv="content-type" content="text/html; charset=UTF-8"> +<link href="sqlite.css" rel="stylesheet"> +<title>The CSV Virtual Table</title> +<!-- path= --> +</head> +<body> +<div class=nosearch> +<a href="index.html"> +<img class="logo" src="images/sqlite370_banner.gif" alt="SQLite" border="0"> +</a> +<div><!-- IE hack to prevent disappearing logo --></div> +<div class="tagline desktoponly"> +Small. Fast. Reliable.<br>Choose any three. +</div> +<div class="menu mainmenu"> +<ul> +<li><a href="index.html">Home</a> +<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a> +<li class='wideonly'><a href='about.html'>About</a> +<li class='desktoponly'><a href="docs.html">Documentation</a> +<li class='desktoponly'><a href="download.html">Download</a> +<li class='wideonly'><a href='copyright.html'>License</a> +<li class='desktoponly'><a href="support.html">Support</a> +<li class='desktoponly'><a href="prosupport.html">Purchase</a> +<li class='search' id='search_menubutton'> +<a href="javascript:void(0)" onclick='toggle_search()'>Search</a> +</ul> +</div> +<div class="menu submenu" id="submenu"> +<ul> +<li><a href='about.html'>About</a> +<li><a href='docs.html'>Documentation</a> +<li><a href='download.html'>Download</a> +<li><a href='support.html'>Support</a> +<li><a href='prosupport.html'>Purchase</a> +</ul> +</div> +<div class="searchmenu" id="searchmenu"> +<form method="GET" action="search"> +<select name="s" id="searchtype"> +<option value="d">Search Documentation</option> +<option value="c">Search Changelog</option> +</select> +<input type="text" name="q" id="searchbox" value=""> +<input type="submit" value="Go"> +</form> +</div> +</div> +<script> +function toggle_div(nm) { +var w = document.getElementById(nm); +if( w.style.display=="block" ){ +w.style.display = "none"; +}else{ +w.style.display = "block"; +} +} +function toggle_search() { +var w = document.getElementById("searchmenu"); +if( w.style.display=="block" ){ +w.style.display = "none"; +} else { +w.style.display = "block"; +setTimeout(function(){ +document.getElementById("searchbox").focus() +}, 30); +} +} +function div_off(nm){document.getElementById(nm).style.display="none";} +window.onbeforeunload = function(e){div_off("submenu");} +/* Disable the Search feature if we are not operating from CGI, since */ +/* Search is accomplished using CGI and will not work without it. */ +if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){ +document.getElementById("search_menubutton").style.display = "none"; +} +/* Used by the Hide/Show button beside syntax diagrams, to toggle the */ +function hideorshow(btn,obj){ +var x = document.getElementById(obj); +var b = document.getElementById(btn); +if( x.style.display!='none' ){ +x.style.display = 'none'; +b.innerHTML='show'; +}else{ +x.style.display = ''; +b.innerHTML='hide'; +} +return false; +} +var antiRobot = 0; +function antiRobotGo(){ +if( antiRobot!=3 ) return; +antiRobot = 7; +var j = document.getElementById("mtimelink"); +if(j && j.hasAttribute("data-href")) j.href=j.getAttribute("data-href"); +} +function antiRobotDefense(){ +document.body.onmousedown=function(){ +antiRobot |= 2; +antiRobotGo(); +document.body.onmousedown=null; +} +document.body.onmousemove=function(){ +antiRobot |= 2; +antiRobotGo(); +document.body.onmousemove=null; +} +setTimeout(function(){ +antiRobot |= 1; +antiRobotGo(); +}, 100) +antiRobotGo(); +} +antiRobotDefense(); +</script> +<div class=fancy> +<div class=nosearch> +<div class="fancy_title"> +The CSV Virtual Table +</div> +</div> + + + + +<h1 id="overview"><span>1. </span>Overview</h1> + +<p> +The CSV virtual table reads +<a href="https://www.ietf.org/rfc/rfc4180.txt">RFC 4180</a> formatted comma-separated +values, and returns that content as if it were rows and columns of an SQL +table. +</p> + +<p> +The CSV virtual table is useful to applications that need to bulk-load +large amounts of comma-separated value content. +The CSV virtual table is also useful as a template source file for +implementing other virtual tables. +</p> + + +<p> +The CSV virtual table is not built into the SQLite amalgamation. +It is available as a +<a href="https://www.sqlite.org/src/artifact?ci=trunk&filename=ext/misc/csv.c">separate source file</a> +that can be compiled into a <a href="loadext.html">loadable extension</a>. +Typical usage of the CSV virtual table from the +<a href="cli.html">command-line shell</a> would be something like this: + +</p><div class="codeblock"><pre>.load ./csv +CREATE VIRTUAL TABLE temp.t1 USING csv(filename='thefile.csv'); +SELECT * FROM t1; +</pre></div> + +<p> +The first line of the script above causes the <a href="cli.html">command-line shell</a> to +read and activate the run-time loadable extension for CSV. For an +application, the equivalent C-language API is +<a href="c3ref/load_extension.html">sqlite3_load_extension()</a>. +Observe that the filename extension (ex: ".dll" or ".so" or ".dylib") is +omitted from the extension filename. Omitting the filename extension is +not required, but it helps in making the script cross-platform. SQLite +will automatically append the appropriate extension. + +</p><p> +The second line above creates a virtual table named "t1" that reads +the content of the file named in the argument. The number and names of +the columns is determined automatically by reading the first line of +content. Other options to the CSV virtual table provide the ability to +take the CSV content from a string rather than a separate file, and give +the programmer more control over the number and names of the columns. +The options are detailed below. The CSV virtual table is usually +created as a TEMP table so that it exists only for the current database +connection and does not become a permanent part of the database schema. +Note that there is no "CREATE TEMP VIRTUAL TABLE" command in SQLite. +Instead, prepend the "temp." schema prefix to the name of the virtual +table. + +</p><p> +The third line of the example shows the virtual table being used, to read +all content of the CSV file. This is perhaps the simplest possible use +of the virtual table. The CSV virtual table can be used anywhere an ordinary +virtual table can be used. One can use the CSV virtual table inside subqueries, +or <a href="lang_with.html">common table expressions</a> or add WHERE, GROUP BY, HAVING, ORDER BY, +and LIMIT clauses as required. + +</p><h1 id="arguments"><span>2. </span>Arguments</h1> + +<p> +The example above showed a single <b>filename='thefile.csv'</b> argument +for the CSV virtual table. But other arguments are also possible. + +</p><ul> +<li><p><b>filename=</b><i>FILENAME</i> +</p><p>The <b>filename=</b> argument specifies an external file from which +CSV content is read. Every CSV virtual table must have either a +<b>filename=</b> argument or a <b>data=</b> argument and not both. + +</p></li><li><p><b>data=</b><i>TEXT</i> +</p><p>The <b>data=</b> argument specifies that <i>TEXT</i> is the literal +content of the CSV file. + +</p></li><li><p><b>schema=</b><i>SCHEMA</i> +</p><p> The <b>schema=</b> argument specifies a <a href="lang_createtable.html">CREATE TABLE</a> statement that +the CSV virtual table passes to the <a href="c3ref/declare_vtab.html">sqlite3_declare_vtab()</a> interface in +order to define the names of the columns in the virtual table. + +</p></li><li><p><b>columns=</b><i>N</i> +</p><p>The <b>columns=</b><i>N</i> argument specifies the number of columns +in the CSV file. +If the input data contains more columns than this, +then the excess columns are ignored. If the input data contains fewer columns, +then extra columns are filled with NULL. +If the <b>columns=</b><i>N</i> argument is omitted, the first line of the +CSV file is read to determine the number of columns. + +</p></li><li><p><b>header=</b><i>BOOLEAN</i><br> +or just<br> +<b>header</b> +</p><p>If the <b>header</b> argument is true then the first row of the CSV file +to be treated as a header rather than as data. The second line of the CSV +file becomes the first row of content. +If the <b>schema=</b> options is omitted, then the first line of the CSV +file determines the names of the columns. +</p></li></ul> + +<h1 id="column_names"><span>3. </span>Column Names</h1> + +<p> +The column names of the virtual table are determined primarily by the +<b>schema=</b> argument. +If the <b>schema=</b> argument is omitted, but <b>header</b> is true, then +the values found in the first line of the CSV file become the column names. +If the <b>schema=</b> argument is omitted and <b>header</b> is false, then +the columns are named "c0", "c1", "c2", and so forth. +</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/csv.in?m=5f8e2137c13221b7b">2018-11-16 01:45:15</a> UTC </small></i></p> + |