Streams Service Review General problems in the Streams Environment List of the general problems observed in the Streams environment databases and list of actions.
You also need the bsddb3 Python module installed; it is included in the Python core in newer versions; however, this module must be compiled against the same version of Berkeley DB that you are using for BDB XML.
Note The topic of Berkeley DB database management is a complex one; users should refer to the Sleepycat docs on this subject (see the references at the end of this chapter) for a thorough treatment of backing up and restoring databases.
For example, to cause an environment to automatically remove log files that are no longer needed (not necessarily the best practice), add this line to the DB_CONFIG file: set_flags DB_LOG_AUTOREMOVE Flags set in the configuration file will silently overrule application configuration.
Utilizing Hierarchy If you're like me, there will be cases in which you'll want to use XQuery not only to pull information out of existing XML but also to use its computing power for its own sake.
XML files for use by processors other than BDB XML, treating them as authoritative and updating them to the database when they change, or treating the database as authoritative and getting XML source from your queries to parse.
However, my experience is that many developers do not reap the benefits of either embedded databases or XML because they lack an understanding of how either can simplify and improve their development, integration, and subsequent support of a software system.
Because we use databases to not just find but also to store and organize our data, entire applications start with database schema design: how many columns, what data types, how much data to allow, what columns to index, and so on.
From the target database, this is the commit SCN for the replication transaction (the APPLY process) and it can be displayed along with the SCN from the source transaction that is recorded in the heartbeat table and replicated to the target.
If we were insistent on maintaining the original files, one option would be to store each individual value as a metadata attribute for the document; unfortunately, many placemarks can be stored in a single document, so this is not an option.
This is largely a matter of preference and architecture, but because the documents in the database have often been imported or created separately from the database, the documents are retained elsewhere and possibly accessed there by the applications.
Because XML is intended to be processed programmatically (not that you wouldn't want to read a book written in XML, of course), it makes the most sense to generate it programmatically, too.
It might make for a cute message to a friend, equivalent to saying this: Name: Jim Brown City: Minneapolis But again, this information would not be particularly useful to an application because it doesn't know for certain what is being described.
This typically isn't an issue because the results set is small to begin with, but keep in mind that if your results sets are potentially large, you won't have indexes to speed up queries when issuing subqueries against them.
Each snapshot taken is identified by a snapshot ID, which is a unique number generated at the time the snapshot.
The rlwrap (readline wrapper) utility provides a command history and editing of keyboard input for any other command.
The method will also accept an XML string (and will generate document names if not provided) if the call supplies the DBXML_GEN_NAME flag.
Each index has an index type, which determines how the nodes will be indexed, whether they should be unique, the data type they are expected to contain, and the types of operations for which they will be used.
ASM's auto generated names can be a bit strange, so creating aliases makes working with ASM files with.
Minutes 29 September 05 General issues Discussion on Streams users privileges (recommendation from Anil Kumar): dba privileges Streams administrator is a requirement.
As you'll soon see, XML fits well into this model of a database as a tool for indexing and searching, without the generally expected need to cajole the data into a limiting table schema.
Adding Indexes Once you have decided on an index type, you can add it via the dbxml shell by using the described index option descriptions or programmatically via the API using either the string descriptions or enumerated types.
RMAN generates a level 0 backup of the file contents at the time of the backup, to be consistent with the.
The database files for Wordnet are simple text files generated by the lexicographer tools used by the department.
Thus Node containers are generally faster to query, but Wholedoc containers retrieve entire documents (as opposed to just nodes or values) more quickly because they don't have to reconstruct the document as with containers of type Node.
Whether you encounter an XML file from a website, in a log, in an email, or in a database, you won't need to know where it came from to have some clue about where it belongs or what it contains.
PDB backup machine general information PDB backup machine (currently itrac330 alias pdb backup) hosts several services critical for the PDB Database Service operation.
After queries (and your XQuery knowledge) are refined, you'll likely either copy them into your own BDB XML application or save them as XQuery files that your application (or another query) can then load and process.
This is more effective than the GATHER_STATS_JOB, because any statistics generated on the table during the.
To maintain indexes, the data itself must also be stored in a way to effectively let the database know when to update an index, which is the main reason why databases contain the data in addition to the index.
Generate a transportable tablespace set that consists of datafiles for the set of tablespaces being transported.
RDA (Remote Diagnostic Agent) is a utility, a set of shell scripts (or) a PERL script, that can be downloaded from.
Mbps that technicians have achieved in the lab, fourth generation mobile users know they have an fascinating future of connection speeds ahead of them2.
Conclusion Although later chapters detail the BDB XML API, much of this chapter dealt with the classes and objects used because they map generally to the physical pieces of the database.
Storing byte offsets rather than line numbers makes for faster lookups because the location can be addresses without reading the whole file up to that line number, something it would have to do in order to count newlines.
Instead, BDB XML generates document names that by default have the syntax dbxml_1cb5e, the last characters being a generated unique hexadecimal number.
The Wholedoc type is intended to store and retrieve small documents; storing documents that approach or are greater than a megabyte using Wholedoc is discouraged, but in practice this will depend on your own application's needs, indexing strategy, and so on.
