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Diffstat (limited to 'docs/programmer_reference/transapp_data_open.html')
| -rw-r--r-- | docs/programmer_reference/transapp_data_open.html | 81 |
1 files changed, 47 insertions, 34 deletions
diff --git a/docs/programmer_reference/transapp_data_open.html b/docs/programmer_reference/transapp_data_open.html index 7315fe12..ca9ca0b4 100644 --- a/docs/programmer_reference/transapp_data_open.html +++ b/docs/programmer_reference/transapp_data_open.html @@ -14,7 +14,7 @@ <body> <div xmlns="" class="navheader"> <div class="libver"> - <p>Library Version 11.2.5.3</p> + <p>Library Version 12.1.6.1</p> </div> <table width="100%" summary="Navigation header"> <tr> @@ -22,9 +22,7 @@ </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="transapp_env_open.html">Prev</a> </td> - <th width="60%" align="center">Chapter 11. - Berkeley DB Transactional Data Store Applications - </th> + <th width="60%" align="center">Chapter 11. Berkeley DB Transactional Data Store Applications </th> <td width="20%" align="right"> <a accesskey="n" href="transapp_put.html">Next</a></td> </tr> </table> @@ -38,10 +36,13 @@ </div> </div> </div> - <p>Next, we open three databases ("color" and "fruit" and "cats"), in the -database environment. Again, our <a href="../api_reference/C/db.html" class="olink">DB</a> database handles are -declared to be free-threaded using the <a href="../api_reference/C/dbopen.html#open_DB_THREAD" class="olink">DB_THREAD</a> flag, and so -may be used by any number of threads we subsequently create.</p> + <p> + Next, we open three databases ("color" and "fruit" and + "cats"), in the database environment. Again, our <a href="../api_reference/C/db.html" class="olink">DB</a> database + handles are declared to be free-threaded using the <a href="../api_reference/C/dbopen.html#open_DB_THREAD" class="olink">DB_THREAD</a> + flag, and so may be used by any number of threads we + subsequently create. + </p> <a id="prog_transapp2"></a> <pre class="programlisting">int main(int argc, char *argv[]) @@ -119,8 +120,10 @@ db_open(DB_ENV *dbenv, DB **dbp, char *name, int dups) *dbp = db; return (0); }</pre> - <p>After opening the database, we can use the <a href="../api_reference/C/db_stat.html" class="olink">db_stat</a> utility to -display information about a database we have created:</p> + <p> + After opening the database, we can use the <a href="../api_reference/C/db_stat.html" class="olink">db_stat</a> utility to + display information about a database we have created: + </p> <pre class="programlisting">prompt> db_stat -h TXNAPP -d color 53162 Btree magic number. 8 Btree version number. @@ -139,30 +142,40 @@ Flags: 0 Number of tree overflow pages. 0 Number of bytes free in tree overflow pages (0% ff). 0 Number of pages on the free list.</pre> - <p>The database open must be enclosed within a transaction in order to be -recoverable. The transaction will ensure that created files are -re-created in recovered environments (or do not appear at all). -Additional database operations or operations on other databases can be -included in the same transaction, of course. In the simple case, where -the open is the only operation in the transaction, an application can -set the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_AUTO_COMMIT" class="olink">DB_AUTO_COMMIT</a> flag instead of creating and managing -its own transaction handle. The <a href="../api_reference/C/envset_flags.html#envset_flags_DB_AUTO_COMMIT" class="olink">DB_AUTO_COMMIT</a> flag will -internally wrap the operation in a transaction, simplifying application -code.</p> - <p>The previous example is the simplest case of transaction protection for -database open. Obviously, additional database operations can be done -in the scope of the same transaction. For example, an application -maintaining a list of the databases in a database environment in a -well-known file might include an update of the list in the same -transaction in which the database is created. Or, an application might -create both a primary and secondary database in a single transaction.</p> - <p><a href="../api_reference/C/db.html" class="olink">DB</a> handles that will later be used for transactionally protected -database operations must be opened within a transaction. Specifying a -transaction handle to database operations using <a href="../api_reference/C/db.html" class="olink">DB</a> handles not -opened within a transaction will return an error. Similarly, not -specifying a transaction handle to database operations that will modify -the database, using handles that were opened within a transaction, will -also return an error.</p> + <p> + The database open must be enclosed within a transaction in + order to be recoverable. The transaction will ensure that + created files are re-created in recovered environments (or do + not appear at all). Additional database operations or + operations on other databases can be included in the same + transaction, of course. In the simple case, where the open is + the only operation in the transaction, an application can set + the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_AUTO_COMMIT" class="olink">DB_AUTO_COMMIT</a> flag instead of creating and managing its + own transaction handle. The <a href="../api_reference/C/envset_flags.html#envset_flags_DB_AUTO_COMMIT" class="olink">DB_AUTO_COMMIT</a> flag will + internally wrap the operation in a transaction, simplifying + application code. + </p> + <p> + The previous example is the simplest case of transaction + protection for database open. Obviously, additional database + operations can be done in the scope of the same transaction. + For example, an application maintaining a list of the + databases in a database environment in a well-known file might + include an update of the list in the same transaction in which + the database is created. Or, an application might create both + a primary and secondary database in a single + transaction. + </p> + <p> + <a href="../api_reference/C/db.html" class="olink">DB</a> handles that will later be used for transactionally + protected database operations must be opened within a + transaction. Specifying a transaction handle to database + operations using <a href="../api_reference/C/db.html" class="olink">DB</a> handles not opened within a transaction + will return an error. Similarly, not specifying a transaction + handle to database operations that will modify the database, + using handles that were opened within a transaction, will also + return an error. + </p> </div> <div class="navfooter"> <hr /> |