performance.po

hibernate 开源框架的代码 jar包希望大家能喜欢

#, fuzzy
msgid ""
msgstr ""
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Content-Type: text/plain; charset=utf-8\n"

#: index.docbook:5
msgid "Improving performance"
msgstr "Mejorando el rendimiento"

#: index.docbook:8
msgid "Fetching strategies"
msgstr "Estrategias de recuperaci&#x00f3;n"

#: index.docbook:10
msgid ""
"A <emphasis>fetching strategy</emphasis> is the strategy Hibernate will use "
"for retrieving associated objects if the application needs to navigate the "
"association. Fetch strategies may be declared in the O/R mapping metadata, "
"or over-ridden by a particular HQL or <literal>Criteria</literal> query."
msgstr ""
"Una <emphasis>estrategia de recuperaci&#x00f3;n</emphasis> es la estrategia "
"que usar&#x00e1; Hibernate para recuperar los objetos asociados cuando la "
"aplicaci&#x00f3;n necesite navegar la asociaci&#x00f3;n. Las estrategias de "
"recuperaci&#x00f3;n pueden ser declaradas en los metadatos de mapeo O/R, o "
"sobrescritas por una consulta HQL o <literal>Criteria</literal> en "
"particular."

#: index.docbook:17
msgid "Hibernate3 defines the following fetching strategies:"
msgstr "Hibernate3 define las siguientes estrategias de recuperaci&#x00f3;n:"

#: index.docbook:23
msgid ""
"<emphasis>Join fetching</emphasis> - Hibernate retrieves the associated "
"instance or collection in the same <literal>SELECT</literal>, using an "
"<literal>OUTER JOIN</literal>."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n por uni&#x00f3;n (join fetching)</emphasis> - "
"Hibernate recupera la instancia asociada o colecci&#x00f3;n en la misma "
"<literal>SELECT</literal>, usando una <literal>OUTER JOIN</literal>."

#: index.docbook:30
msgid ""
"<emphasis>Select fetching</emphasis> - a second <literal>SELECT</literal> is "
"used to retrieve the associated entity or collection. Unless you explicitly "
"disable lazy fetching by specifying <literal>lazy=\"false\"</literal>, this "
"second select will only be executed when you actually access the association."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n por selecci&#x00f3;n (select fetching)</"
"emphasis> - se usa una segunda <literal>SELECT</literal> para recuperar la "
"entidad asociada o colecci&#x00f3;n. A menos que deshabilites expl&#x00ed;"
"citamente la recuperaci&#x00f3;n perezosa especificando <literal>lazy=\"false"
"\"</literal>, la segunda selecci&#x00f3;n s&#x00f3;lo ser&#x00e1; ejecutada "
"cuando realmente accedas a la asociaci&#x00f3;n."

#: index.docbook:39
msgid ""
"<emphasis>Subselect fetching</emphasis> - a second <literal>SELECT</literal> "
"is used to retrieve the associated collections for all entities retrieved in "
"a previous query or fetch. Unless you explicitly disable lazy fetching by "
"specifying <literal>lazy=\"false\"</literal>, this second select will only "
"be executed when you actually access the association."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n por subselecci&#x00f3;n (subselect fetching)</"
"emphasis> - se usa una segunda <literal>SELECT</literal> para recuperar las "
"colecciones asociadas de todas las entidades recuperadas en una consulta o "
"recuperaci&#x00f3;n previa. A menos que deshabilites expl&#x00ed;citamente "
"la recuperaci&#x00f3;n perezosa especificando <literal>lazy=\"false\"</"
"literal>, esta segunda selecci&#x00f3;n s&#x00f3;lo ser&#x00e1; ejecutada "
"cuando realmente accedas a la asociaci&#x00f3;n."

#: index.docbook:48
msgid ""
"<emphasis>Batch fetching</emphasis> - an optimization strategy for select "
"fetching - Hibernate retrieves a batch of entity instances or collections in "
"a single <literal>SELECT</literal>, by specifying a list of primary keys or "
"foreign keys."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n en lote</emphasis> - una estrategia de "
"optimizaci&#x00f3;n para la recuperaci&#x00f3;n por selecci&#x00f3;n - "
"Hibernate recupera un lote de instancias de entidad o colecciones en una "
"sola <literal>SELECT</literal>, especificando una lista de claves primarias "
"o de claves for&#x00e1;neas."

#: index.docbook:57
msgid "Hibernate also distinguishes between:"
msgstr "Hibernate tambi&#x00e9;n distingue entre:"

#: index.docbook:63
msgid ""
"<emphasis>Immediate fetching</emphasis> - an association, collection or "
"attribute is fetched immediately, when the owner is loaded."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n inmediata</emphasis> - una asociaci&#x00f3;n, "
"colecci&#x00f3;n o atributo es recuperado inmediatamente, cuando el "
"due&#x00f1;o es cargado."

#: index.docbook:69
msgid ""
"<emphasis>Lazy collection fetching</emphasis> - a collection is fetched when "
"the application invokes an operation upon that collection. (This is the "
"default for collections.)"
msgstr ""
"<emphasis>Recuperaci&#x00f3;n perezosa de colecciones</emphasis> - se "
"recupera una colecci&#x00f3;n cuando la aplicaci&#x00f3;n invoca una "
"operaci&#x00f3;n sobre la colecci&#x00f3;n. (Esto es por defecto para las "
"colecciones.)"

#: index.docbook:76
msgid ""
"<emphasis>\"Extra-lazy\" collection fetching</emphasis> - individual "
"elements of the collection are accessed from the database as needed. "
"Hibernate tries not to fetch the whole collection into memory unless "
"absolutely needed (suitable for very large collections)"
msgstr ""
"<emphasis>\"Extra-lazy\" collection fetching</emphasis> - individual "
"elements of the collection are accessed from the database as needed. "
"Hibernate tries not to fetch the whole collection into memory unless "
"absolutely needed (suitable for very large collections)"

#: index.docbook:84
msgid ""
"<emphasis>Proxy fetching</emphasis> - a single-valued association is fetched "
"when a method other than the identifier getter is invoked upon the "
"associated object."
msgstr ""
"<emphasis>Proxy fetching</emphasis> - a single-valued association is fetched "
"when a method other than the identifier getter is invoked upon the "
"associated object."

#: index.docbook:91
msgid ""
"<emphasis>\"No-proxy\" fetching</emphasis> - a single-valued association is "
"fetched when the instance variable is accessed. Compared to proxy fetching, "
"this approach is less lazy (the association is fetched even when only the "
"identifier is accessed) but more transparent, since no proxy is visible to "
"the application. This approach requires buildtime bytecode instrumentation "
"and is rarely necessary."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n por proxy</emphasis> - se recupera una "
"asociaci&#x00f3;n monovaluada cuando se invoca un m&#x00e9;todo que no sea "
"el getter del identificador sobre el objeto asociado."

#: index.docbook:101
msgid ""
"<emphasis>Lazy attribute fetching</emphasis> - an attribute or single valued "
"association is fetched when the instance variable is accessed. This approach "
"requires buildtime bytecode instrumentation and is rarely necessary."
msgstr ""
"<emphasis>Recuperaci&#x00f3;n perezosa de atributos</emphasis> - se recupera "
"un atributo o una asociaci&#x00f3;n monovaluada cuando se accede a la "
"variable de instancia (requiere instrumentaci&#x00f3;n del bytecode en "
"tiempo de ejecuci&#x00f3;n). Este enfoque es raramente necesario."

#: index.docbook:110
msgid ""
"We have two orthogonal notions here: <emphasis>when</emphasis> is the "
"association fetched, and <emphasis>how</emphasis> is it fetched (what SQL is "
"used). Don't confuse them! We use <literal>fetch</literal> to tune "
"performance. We may use <literal>lazy</literal> to define a contract for "
"what data is always available in any detached instance of a particular class."
msgstr ""
"Aqu&#x00ed; tenemos dos nociones ortogonales: <emphasis>cu&#x00e1;ndo</"
"emphasis> se recupera la aplicaci&#x00f3;n, y <emphasis>c&#x00f3;mo</"
"emphasis> es recuperada (qu&#x00e9; SQL es usado). &#x00a1;No las confundas! "
"Usamos <literal>fetch</literal> para afinar el rendimiento. Podemos usar "
"<literal>lazy</literal> para definir un contrato sobre qu&#x00e9; datos "
"est&#x00e1;n siempre disponibles en cualquier instancia separada de una "
"clase en particular."

#: index.docbook:119
msgid "Working with lazy associations"
msgstr "Trabajando con asociaciones perezosas"

#: index.docbook:121
msgid ""
"By default, Hibernate3 uses lazy select fetching for collections and lazy "
"proxy fetching for single-valued associations. These defaults make sense for "
"almost all associations in almost all applications."
msgstr ""
"Por defecto, Hibernate3 usa una recuperaci&#x00f3;n perezosa por "
"selecci&#x00f3;n para colecciones y una recuperaci&#x00f3;n por proxy "
"perezosa para asociaciones monovaluadas. Estas pol&#x00ed;ticas por defecto "
"tienen sentido para casi todas las asociaciones en casi todas las "
"aplicaciones."

#: index.docbook:127
msgid ""
"<emphasis>Note:</emphasis> if you set <literal>hibernate."
"default_batch_fetch_size</literal>, Hibernate will use the batch fetch "
"optimization for lazy fetching (this optimization may also be enabled at a "
"more granular level)."
msgstr ""
"<emphasis>Nota:</emphasis> si estableces <literal>hibernate."
"default_batch_fetch_size</literal>, Hibernate usar&#x00e1; la "
"optimizaci&#x00f3;n de recuperaci&#x00f3;n en lotes para recuperaci&#x00f3;n "
"perezosa (esta optimizaci&#x00f3;n tambi&#x00e9;n puede ser habilitada a un "
"nivel m&#x00e1;s granularizado)."

#: index.docbook:134
msgid ""
"However, lazy fetching poses one problem that you must be aware of. Access "
"to a lazy association outside of the context of an open Hibernate session "
"will result in an exception. For example:"
msgstr ""
"Sin embargo, la recuperaci&#x00f3;n perezosa plantea un problema del que "
"tienes que estar al tanto. Acceder a una asociaci&#x00f3;n perezosa fuera "
"del contexto de una sesi&#x00f3;n de Hibernate abierta resultar&#x00e1; en "
"una excepci&#x00f3;n. Por ejemplo:"

#: index.docbook:140
msgid ""
"<![CDATA[s = sessions.openSession();\n"
"Transaction tx = s.beginTransaction();\n"
"            \n"
"User u = (User) s.createQuery(\"from User u where u.name=:userName\")\n"
"    .setString(\"userName\", userName).uniqueResult();\n"
"Map permissions = u.getPermissions();\n"
"\n"
"tx.commit();\n"
"s.close();\n"
"\n"
"Integer accessLevel = (Integer) permissions.get(\"accounts\");  // Error!]]>"
msgstr ""
"<![CDATA[s = sessions.openSession();\n"
"Transaction tx = s.beginTransaction();\n"
"            \n"
"User u = (User) s.createQuery(\"from User u where u.name=:userName\")\n"
"    .setString(\"userName\", userName).uniqueResult();\n"
"Map permissions = u.getPermissions();\n"
"\n"
"tx.commit();\n"
"s.close();\n"
"\n"
"Integer accessLevel = (Integer) permissions.get(\"accounts\");  // Error!]]>"

#: index.docbook:142
msgid ""
"Since the permissions collection was not initialized when the "
"<literal>Session</literal> was closed, the collection will not be able to "
"load its state. <emphasis>Hibernate does not support lazy initialization for "
"detached objects</emphasis>. The fix is to move the code that reads from the "
"collection to just before the transaction is committed."
msgstr ""
"Ya que la colecci&#x00f3;n de permisos no fue inicializada cuando se "
"cerr&#x00f3; la <literal>Session</literal>, la colecci&#x00f3;n no "
"ser&#x00e1; capaz de cargar su estado. <emphasis>Hibernate no soporta la "
"inicializaci&#x00f3;n perezosa de objetos separados</emphasis>. La "
"soluci&#x00f3;n es mover el c&#x00f3;digo que lee de la colecci&#x00f3;n a "
"justo antes que la transacci&#x00f3;n sea comprometida."

#: index.docbook:150
msgid ""
"Alternatively, we could use a non-lazy collection or association, by "
"specifying <literal>lazy=\"false\"</literal> for the association mapping. "
"However, it is intended that lazy initialization be used for almost all "
"collections and associations. If you define too many non-lazy associations "
"in your object model, Hibernate will end up needing to fetch the entire "
"database into memory in every transaction!"
msgstr ""
"Alternativamente, podr&#x00ed;amos usar una colecci&#x00f3;n no perezosa o "
"asociaci&#x00f3;n, especificando <literal>lazy=\"false\"</literal> para el "
"mapeo de asociaci&#x00f3;n. Sin embargo, est&#x00e1; pensado que la "
"inicializaci&#x00f3;n perezosa sea usada para casi todas las colecciones y "
"asociaciones. &#x00a1;Si defines demasiadas asociaciones no perezosas en tu "
"modelo de objetos, Hibernate terminar&#x00e1; necesitando recuperar la base "
"de datos entera en cada transacci&#x00f3;n!"

#: index.docbook:159
msgid ""
"On the other hand, we often want to choose join fetching (which is non-lazy "
"by nature) instead of select fetching in a particular transaction. We'll now "
"see how to customize the fetching strategy. In Hibernate3, the mechanisms "
"for choosing a fetch strategy are identical for single-valued associations "
"and collections."
msgstr ""
"Por otro lado, frecuentemente necesitamos elegir la recuperaci&#x00f3;n por "
"uni&#x00f3;n (que es no perezosa por naturaleza) en vez de la "
"recuperaci&#x00f3;n por selecci&#x00f3;n en una transacci&#x00f3;n en "
"particular. Veremos ahora c&#x00f3;mo personalizar la estrategia de "
"recuperaci&#x00f3;n. En Hibernate3, los mecanismos para elegir una "
"estrategia de recuperaci&#x00f3;n son id&#x00e9;nticas a las de las "
"asociaciones monovaluadas y colecciones."

#: index.docbook:170
msgid "Tuning fetch strategies"
msgstr "Afinando las estrategias de recuperaci&#x00f3;n"

#: index.docbook:172
msgid ""
"Select fetching (the default) is extremely vulnerable to N+1 selects "
"problems, so we might want to enable join fetching in the mapping document:"
msgstr ""
"La recuperaci&#x00f3;n por selecci&#x00f3;n (la preestablecida) es "
"extremadamente vulnerable a problemas de selecci&#x00f3;n N+1, de modo "
"querr&#x00ed;amos habilitar la recuperaci&#x00f3;n por uni&#x00f3;n (join "
"fetching) en el documento de mapeo:"

#: index.docbook:177
msgid ""