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diff --git a/db/docs/api_c/db_associate.html b/db/docs/api_c/db_associate.html new file mode 100644 index 000000000..56ea224ea --- /dev/null +++ b/db/docs/api_c/db_associate.html @@ -0,0 +1,156 @@ +<!--Id: db_associate.so,v 10.9 2001/05/05 01:49:09 bostic Exp --> +<!--Copyright 1997-2001 by Sleepycat Software, Inc.--> +<!--All rights reserved.--> +<html> +<head> +<title>Berkeley DB: DB->associate</title> +<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> +<meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++"> +</head> +<body bgcolor=white> + <a name="2"><!--meow--></a> +<table width="100%"><tr valign=top> +<td> +<h1>DB->associate</h1> +</td> +<td align=right> +<a href="../api_c/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> +</td></tr></table> +<hr size=1 noshade> +<tt> +<h3><pre> +#include <db.h> +<p> +DB->associate(DB *primary, DB *secondary, + int (*callback)(DB *, const DBT *, const DBT *, DBT *), + u_int32_t flags); +</pre></h3> +<h1>Description</h1> +<p>The DB->associate function is used to declare one database a +secondary index for a primary database. After a secondary database has +been "associated" with a primary database, all updates to the primary +will be automatically reflected in the secondary and all reads from the +secondary will return corresponding data from the primary. Note that +as primary keys must be unique for secondary indices to work, the +primary database must be configured without support for duplicate data +items. See <a href="../ref/am/second.html">Secondary indices</a> for +more information. +<p>The <b>primary</b> argument should be a database handle for the primary +database that is to be indexed. +The <b>secondary</b> argument should be an open database handle of +either a newly created and empty database that is to be used to store +a secondary index, or of a database that was previously associated with +the same primary and contains a secondary index. Note that it is not +safe to associate as a secondary database a handle that is in use by +another thread of control or has open cursors. If the handle was opened +with the <a href="../api_c/env_open.html#DB_THREAD">DB_THREAD</a> flag it is safe to use it in multiple threads +of control after the DB->associate function has returned. Note also +that either secondary keys must be unique or the secondary database must +be configured with support for duplicate data items. +<p>The <b>callback</b> argument should refer to a callback function that +creates a secondary key from a given primary key and data pair. When +called, the first argument will be the secondary DB handle; the +second and third arguments will be <a href="../api_c/dbt.html">DBT</a>s containing a primary +key and datum respectively; and the fourth argument will be a zeroed +DBT in which the callback function should fill in <b>data</b> and +<b>size</b> fields that describe the secondary key. +<p>If the callback function needs to allocate memory for the <b>data</b> +field rather than simply pointing into the primary key or datum, the +<b>flags</b> field of the returned <a href="../api_c/dbt.html">DBT</a> should be set to +DB_DBT_APPMALLOC, which indicates that Berkeley DB should free the +memory when it is done with it. +<p>If any key/data pair in the primary yields a null secondary key and +should be left out of the secondary index, the callback function may +optionally return DB_DONOTINDEX. Otherwise, the callback +function should return 0 in case of success or any other integer error +code in case of failure; the error code will be returned from the Berkeley DB +interface call that initiated the callback. Note that if the callback +function returns DB_DONOTINDEX for any key/data pairs in the +primary database, the secondary index will not contain any reference to +those key/data pairs, and such operations as cursor iterations and range +queries will reflect only the corresponding subset of the database. If +this is not desirable, the application should ensure that the callback +function is well-defined for all possible values and never returns +DB_DONOTINDEX. +<p>The callback argument may be NULL if and only if both the primary and +secondary database handles were opened with the <a href="../api_c/db_open.html#DB_RDONLY">DB_RDONLY</a> flag. +<p>The <b>flags</b> value must be set to 0 or +the following value: +<p><dl compact> +<p><dt><a name="DB_CREATE">DB_CREATE</a><dd>If the secondary database is empty, walk through the primary and create +an index to it in the empty secondary. Note that this operation is +potentially very expensive. +<p>If the secondary database has been opened in an environment configured +with transactions, each put necessary for its creation will be done in +the context of a transaction created for the purpose. +<p>Note that care should be taken not to use a newly-created secondary +database in another thread of control until the DB->associate +call has returned successfully in the first thread. +</dl> +<h1>Errors</h1> +<p>The DB->associate function may fail and return a non-zero error for the following conditions: +<p><dl compact> +<p><dt>EINVAL<dd>An invalid flag value or parameter was specified. +<p>The secondary database handle has already been associated with this or +another database handle. +<p>The secondary database handle is not open. +<p>The primary database has been configured to allow duplicates. +</dl> +<p>The DB->associate function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. +If a catastrophic error has occurred, the DB->associate function may fail and return +<a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>, in which case all subsequent Berkeley DB calls will fail +in the same way. +<h1>See Also</h1> +<a href="../api_c/db_create.html">db_create</a>, +<a href="../api_c/db_associate.html">DB->associate</a>, +<a href="../api_c/db_close.html">DB->close</a>, +<a href="../api_c/db_cursor.html">DB->cursor</a>, +<a href="../api_c/db_del.html">DB->del</a>, +<a href="../api_c/db_err.html">DB->err</a>, <a href="../api_c/db_err.html">DB->errx</a> +<a href="../api_c/db_fd.html">DB->fd</a>, +<a href="../api_c/db_get.html">DB->get</a>, +<a href="../api_c/db_get.html">DB->pget</a>, +<a href="../api_c/db_get_byteswapped.html">DB->get_byteswapped</a>, +<a href="../api_c/db_get_type.html">DB->get_type</a>, +<a href="../api_c/db_join.html">DB->join</a>, +<a href="../api_c/db_key_range.html">DB->key_range</a>, +<a href="../api_c/db_open.html">DB->open</a>, +<a href="../api_c/db_put.html">DB->put</a>, +<a href="../api_c/db_remove.html">DB->remove</a>, +<a href="../api_c/db_rename.html">DB->rename</a>, +<a href="../api_c/db_set_alloc.html">DB->set_alloc</a>, +<a href="../api_c/db_set_append_recno.html">DB->set_append_recno</a>, +<a href="../api_c/db_set_bt_compare.html">DB->set_bt_compare</a>, +<a href="../api_c/db_set_bt_minkey.html">DB->set_bt_minkey</a>, +<a href="../api_c/db_set_bt_prefix.html">DB->set_bt_prefix</a>, +<a href="../api_c/db_set_cachesize.html">DB->set_cachesize</a>, +<a href="../api_c/db_set_dup_compare.html">DB->set_dup_compare</a>, +<a href="../api_c/db_set_errcall.html">DB->set_errcall</a>, +<a href="../api_c/db_set_errfile.html">DB->set_errfile</a>, +<a href="../api_c/db_set_errpfx.html">DB->set_errpfx</a>, +<a href="../api_c/db_set_feedback.html">DB->set_feedback</a>, +<a href="../api_c/db_set_flags.html">DB->set_flags</a>, +<a href="../api_c/db_set_h_ffactor.html">DB->set_h_ffactor</a>, +<a href="../api_c/db_set_h_hash.html">DB->set_h_hash</a>, +<a href="../api_c/db_set_h_nelem.html">DB->set_h_nelem</a>, +<a href="../api_c/db_set_lorder.html">DB->set_lorder</a>, +<a href="../api_c/db_set_pagesize.html">DB->set_pagesize</a>, +<a href="../api_c/db_set_paniccall.html">DB->set_paniccall</a>, +<a href="../api_c/db_set_q_extentsize.html">DB->set_q_extentsize</a>, +<a href="../api_c/db_set_re_delim.html">DB->set_re_delim</a>, +<a href="../api_c/db_set_re_len.html">DB->set_re_len</a>, +<a href="../api_c/db_set_re_pad.html">DB->set_re_pad</a>, +<a href="../api_c/db_set_re_source.html">DB->set_re_source</a>, +<a href="../api_c/db_stat.html">DB->stat</a>, +<a href="../api_c/db_sync.html">DB->sync</a>, +<a href="../api_c/db_truncate.html">DB->truncate</a>, +<a href="../api_c/db_upgrade.html">DB->upgrade</a>, +and +<a href="../api_c/db_verify.html">DB->verify</a>. +</tt> +<table width="100%"><tr><td><br></td><td align=right> +<a href="../api_c/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> +</td></tr></table> +<p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> +</body> +</html> |