181 lines
7.0 KiB
HTML
181 lines
7.0 KiB
HTML
<!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>Extract Metadata About A Column Of A 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;
|
|
}
|
|
</script>
|
|
</div>
|
|
<!-- keywords: sqlite3_table_column_metadata -->
|
|
<div class=nosearch>
|
|
<a href="intro.html"><h2>SQLite C Interface</h2></a>
|
|
<h2>Extract Metadata About A Column Of A Table</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_table_column_metadata(
|
|
sqlite3 *db, /* Connection handle */
|
|
const char *zDbName, /* Database name or NULL */
|
|
const char *zTableName, /* Table name */
|
|
const char *zColumnName, /* Column name */
|
|
char const **pzDataType, /* OUTPUT: Declared data type */
|
|
char const **pzCollSeq, /* OUTPUT: Collation sequence name */
|
|
int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
|
|
int *pPrimaryKey, /* OUTPUT: True if column part of PK */
|
|
int *pAutoinc /* OUTPUT: True if column is auto-increment */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
|
|
information about column C of table T in database D
|
|
on <a href="../c3ref/sqlite3.html">database connection</a> X. The sqlite3_table_column_metadata()
|
|
interface returns SQLITE_OK and fills in the non-NULL pointers in
|
|
the final five arguments with appropriate values if the specified
|
|
column exists. The sqlite3_table_column_metadata() interface returns
|
|
SQLITE_ERROR if the specified column does not exist.
|
|
If the column-name parameter to sqlite3_table_column_metadata() is a
|
|
NULL pointer, then this routine simply checks for the existence of the
|
|
table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
|
|
does not. If the table name parameter T in a call to
|
|
sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
|
|
undefined behavior.</p>
|
|
|
|
<p>The column is identified by the second, third and fourth parameters to
|
|
this function. The second parameter is either the name of the database
|
|
(i.e. "main", "temp", or an attached database) containing the specified
|
|
table or NULL. If it is NULL, then all attached databases are searched
|
|
for the table using the same algorithm used by the database engine to
|
|
resolve unqualified table references.</p>
|
|
|
|
<p>The third and fourth parameters to this function are the table and column
|
|
name of the desired column, respectively.</p>
|
|
|
|
<p>Metadata is returned by writing to the memory locations passed as the 5th
|
|
and subsequent parameters to this function. Any of these arguments may be
|
|
NULL, in which case the corresponding element of metadata is omitted.</p>
|
|
|
|
<p><blockquote>
|
|
<table border="1">
|
|
<tr><th> Parameter <th> Output<br>Type <th> Description</p>
|
|
|
|
<p><tr><td> 5th <td> const char* <td> Data type
|
|
<tr><td> 6th <td> const char* <td> Name of default collation sequence
|
|
<tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
|
|
<tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
|
|
<tr><td> 9th <td> int <td> True if column is <a href="../autoinc.html">AUTOINCREMENT</a>
|
|
</table>
|
|
</blockquote></p>
|
|
|
|
<p>The memory pointed to by the character pointers returned for the
|
|
declaration type and collation sequence is valid until the next
|
|
call to any SQLite API function.</p>
|
|
|
|
<p>If the specified table is actually a view, an <a href="../rescode.html">error code</a> is returned.</p>
|
|
|
|
<p>If the specified column is "rowid", "oid" or "_rowid_" and the table
|
|
is not a <a href="../withoutrowid.html">WITHOUT ROWID</a> table and an
|
|
<a href="../lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column has been explicitly declared, then the output
|
|
parameters are set for the explicitly declared column. If there is no
|
|
<a href="../lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column, then the outputs
|
|
for the <a href="../lang_createtable.html#rowid">rowid</a> are set as follows:</p>
|
|
|
|
<p><pre>
|
|
data type: "INTEGER"
|
|
collation sequence: "BINARY"
|
|
not null: 0
|
|
primary key: 1
|
|
auto increment: 0
|
|
</pre></p>
|
|
|
|
<p>This function causes all database schemas to be read from disk and
|
|
parsed, if that has not already been done, and returns an error if
|
|
any errors are encountered while loading the schema.
|
|
</p><p>See also lists of
|
|
<a href="objlist.html">Objects</a>,
|
|
<a href="constlist.html">Constants</a>, and
|
|
<a href="funclist.html">Functions</a>.</p>
|