162 lines
5.0 KiB
HTML
162 lines
5.0 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<title>LuaSQL: Database connectivity for the Lua programming language</title>
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<link rel="stylesheet" href="doc.css" type="text/css"/>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
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</head>
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<body>
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<div id="container">
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<div id="product">
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<div id="product_logo"><a href="http://www.keplerproject.org">
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<img alt="LuaSQL logo" src="luasql.png"/>
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</a></div>
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<div id="product_name"><big><b>LuaSQL</b></big></div>
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<div id="product_description">Database connectivity for the Lua programming language</div>
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</div> <!-- id="product" -->
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<div id="main">
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<div id="navigation">
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<h1>LuaSQL</h1>
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<ul>
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<li><a href="index.html">Home</a>
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<ul>
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<li><a href="index.html#overview">Overview</a></li>
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<li><a href="index.html#status">Status</a></li>
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<li><a href="index.html#download">Download</a></li>
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<li><a href="index.html#credits">Credits</a></li>
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<li><a href="index.html#contact">Contact us</a></li>
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</ul>
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</li>
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<li><a href="manual.html">Manual</a>
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<ul>
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<li><a href="manual.html#introduction">Introduction</a></li>
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<li><a href="manual.html#compiling">Compiling</a></li>
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<li><a href="manual.html#installation">Installation</a></li>
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<li><a href="manual.html#errors">Error handling</a></li>
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<li><a href="manual.html#drivers">Drivers</a></li>
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<li><a href="manual.html#environment_object">Environment</a></li>
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<li><a href="manual.html#connection_object">Connection</a></li>
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<li><a href="manual.html#cursor_object">Cursor</a></li>
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<li><a href="manual.html#postgres_extensions">PostgreSQL</a></li>
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<li><a href="manual.html#mysql_extensions">MySQL</a></li>
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<li><a href="manual.html#oracle_extensions">Oracle</a></li>
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<li><a href="manual.html#sqlite3_extensions">SQLite3</a></li>
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</ul>
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</li>
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<li><strong>Examples</strong></li>
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<li><a href="history.html">History</a></li>
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<li><a href="http://github.com/keplerproject/luasql">Project</a>
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<ul>
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<li><a href="http://github.com/keplerproject/luasql/issues">Bug Tracker</a></li>
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</ul>
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</li>
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<li><a href="license.html">License</a></li>
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</ul>
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</div> <!-- id="navigation" -->
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<div id="content">
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<h2><a name="examples"></a>Examples</h2>
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<p>Here is an example of the basic use of the library.
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After that, another example shows how to create an
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<a href="#iterator_example">iterator</a> over the result of a SELECT
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query.</p>
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<h3><a name="basic_use"></a>Basic use</h3>
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<pre class="example">
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-- load driver
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local driver = require "luasql.postgres"
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-- create environment object
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env = assert (driver.postgres())
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-- connect to data source
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con = assert (env:connect("luasql-test"))
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-- reset our table
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res = con:execute"DROP TABLE people"
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res = assert (con:execute[[
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CREATE TABLE people(
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name varchar(50),
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email varchar(50)
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)
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]])
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-- add a few elements
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list = {
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{ name="Jose das Couves", email="jose@couves.com", },
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{ name="Manoel Joaquim", email="manoel.joaquim@cafundo.com", },
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{ name="Maria das Dores", email="maria@dores.com", },
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}
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for i, p in pairs (list) do
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res = assert (con:execute(string.format([[
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INSERT INTO people
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VALUES ('%s', '%s')]], p.name, p.email)
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))
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end
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-- retrieve a cursor
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cur = assert (con:execute"SELECT name, email from people")
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-- print all rows, the rows will be indexed by field names
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row = cur:fetch ({}, "a")
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while row do
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print(string.format("Name: %s, E-mail: %s", row.name, row.email))
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-- reusing the table of results
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row = cur:fetch (row, "a")
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end
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-- close everything
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cur:close() -- already closed because all the result set was consumed
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con:close()
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env:close()
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</pre>
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<p>And the output of this script should be:</p>
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<pre class="example">
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Name: Jose das Couves, E-mail: jose@couves.com
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Name: Manoel Joaquim, E-mail: manoel.joaquim@cafundo.com
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Name: Maria das Dores, E-mail: maria@dores.com
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</pre>
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<h3><a name="iterator_example"></a>Iterator</h3>
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<p>It may be useful to offer an iterator for the resulting rows:</p>
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<pre class="example">
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function rows (connection, sql_statement)
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local cursor = assert (connection:execute (sql_statement))
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return function ()
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return cursor:fetch()
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end
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end
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</pre>
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<p>Here is how the iterator is used:</p>
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<pre class="example">
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env = assert (require"luasql.mysql".mysql())
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con = assert (env:connect"my_db")
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for id, name, address in rows (con, "select * from contacts") do
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print (string.format ("%s: %s", name, address))
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end
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</pre>
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<p>Obviously, the code above only works if there is a table called contacts with the columns id, name and address in this order. At the end of the loop the cursor will be automatically closed by the driver.</p>
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</div> <!-- id="content" -->
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</div> <!-- id="main" -->
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<div id="about">
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<p><a href="http://validator.w3.org/check?uri=referer">Valid XHTML 1.0!</a></p>
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<p><small>$Id: examples.html,v 1.16 2008/06/11 00:26:13 jasonsantos Exp $</small></p>
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</div> <!-- id="about" -->
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</div> <!-- id="container" -->
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</body>
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</html>
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