Consulta sobre estructuras de datos
Las estructuras de datos se pueden consultar en el caché si tienen atributos de búsqueda asociados con ellos durante la creación de la estructura de datos. Estos atributos de búsqueda incluyen:
Requisitos previos
- Para obtener información sobre los requisitos previos estándar necesarios para trabajar con todos NCache características del lado del cliente, consulte la página proporcionada en Requisitos previos de la API del lado del cliente.
- Para obtener detalles de la API, consulte: Dolor, ConsultaComando, Lector de ICache, Servicio de búsqueda, Ejecutar Lector, Getvalue, Lista distribuida, Obtener datos de grupo, Recuento de campo, Diccionario IDistribuido, Obtener por etiqueta.
- Para obtener información sobre los requisitos previos estándar necesarios para trabajar con todos NCache características del lado del cliente, consulte la página proporcionada en Requisitos previos de la API del lado del cliente.
- Para obtener detalles de la API, consulte: cache, ConsultaComando, Lector de caché, obtener servicio de búsqueda, ejecutarLector, getFieldCount, getValue, Lista distribuida, obtener datos de grupo, Atributos de estructura de datos, Mapa distribuido, obtener por etiqueta.
- Para obtener información sobre los requisitos previos estándar necesarios para trabajar con todos NCache características del lado del cliente, consulte la página proporcionada en Requisitos previos de la API del lado del cliente.
- Para obtener detalles de la API, consulte: cache, ConsultaComando, Servicio de búsqueda, obtener servicio de búsqueda, ejecutarLector, getFieldCount, getValue, obtener datos de grupo, Lector de caché, Atributos de estructura de datos, obtener por etiqueta.
- Para obtener información sobre los requisitos previos estándar necesarios para trabajar con todos NCache características del lado del cliente, consulte la página proporcionada en Requisitos previos de la API del lado del cliente.
- Para obtener detalles de la API, consulte: cache, ConsultaComando, Lector de caché, ejecutar_lector, Servicio de búsqueda, get_search_service, Atributos de estructura de datos, get_field_count, obtener_valor, obtener_datos_grupo, obtener_por_etiqueta.
Buscar estructuras de datos por grupos
consulta SQL
El siguiente ejemplo de código recupera todos los elementos del caché que se han asociado con un grupo específico, Electrónica. El Grupo se puede asociar mediante DataTypeAttributes
clase durante la creación de la estructura de datos.
Importante:
- Si hay varias listas especificadas en el grupo, todas ellas se devolverán en un resultado, siempre que sus estructuras de datos sean similares.
- Para varios elementos de caché, por ejemplo, si un
CacheItem
y una lista pertenecen al mismo grupo, debe asegurarse de que los datos se manejen en consecuencia.
// Preconditions: Cache is already connected
// Items with groups exist in cache
// Custom class is query indexed through the NCache Management Center or config.ncconf
// Search for items with group
// Provide Fully Qualified Name (FQN) of your custom class
string query = "SELECT ProductID FROM FQN.Customer WHERE $Group$ = ?";
/// Use QueryCommand for query execution
var queryCommand = new QueryCommand(query);
// Providing parameters for query
queryCommand.Parameters.Add("$Group$", "Electronics");
// Executing QueryCommand through ICacheReader
ICacheReader reader = cache.SearchService.ExecuteReader(queryCommand);
// Check if the result set is not empty
if (reader.FieldCount > 0)
{
while (reader.Read())
{
string ProductID = reader.GetValue<string>(1);
// Perform operations
}
}
else
{
// Null query result set retrieved
}
// Preconditions: Cache is already connected
// Items with groups exist in cache
// Custom class is query indexed through NCache Management Center or config.ncconf
// Search for items with group
// Provide Fully Qualified Name (FQN) of your custom class
String query = "SELECT productID FROM FQN.Customer WHERE $Group$ = ?";
// Use QueryCommand for query execution
var queryCommand = new QueryCommand(query);
// Providing parameters for query
queryCommand.getParameters().put("$Group$", "Electronics");
// Executing QueryCommand through CacheReader
CacheReader reader = cache.getSearchService().executeReader(queryCommand);
// Check if the result set is not empty
if (reader.getFieldCount() > 0) {
while (reader.read()) {
String productID = reader.getValue(1, String.class);
// Perform operations
}
} else {
// Null query result set retrieved
}
// This is an async method
// Preconditions: Cache is already connected
// Items with groups exist in cache
// Custom class is query indexed through the NCache Management Center or config.ncconf
// Search for items with group
// Provide Fully Qualified Name (FQN) of your custom class
var query = "SELECT productID FROM FQN.Customer WHERE $Group$ = ?";
/// Use QueryCommand for query execution
var queryCommand = new ncache.QueryCommand(query);
// Providing parameters for query
let map = new Map();
var parameters = map.set("$Group$", "Electronics");
queryCommand.setParameters(parameters);
// Executing QueryCommand through CacheReader
var searchService = await this.cache.getSearchService();
var reader = await searchService.executeReader(queryCommand);
// Check if the result set is not empty
if (reader.getFieldCount() > 0) {
while (reader.read()) {
var productID = reader.getValue(1, Number());
// Perform operations
}
} else {
// Null query result set retrieved
}
# Preconditions: Cache is already connected
# Items with groups exist in cache
# Custom class is query indexed through NCache Management Center or config.ncconf
# Search for items with group
# Provide Fully Qualified Name (FQN) of your custom class
query = "SELECT product_id FROM FQN.Customer WHERE $Group$ = ?"
# Use QueryCommand for query execution
query_command = ncache.QueryCommand(query)
# Providing parameters for query
parameters = {"$Group$": "Electronics"}
query_command.set_parameters(parameters)
# Executing QueryCommand through CacheReader
search_service = cache.get_search_service()
reader = search_service.execute_reader(query_command)
# Check if the result set is not empty
if reader.get_field_count() > 0:
while reader.read():
product_id = reader.get_value(str, 1)
# Perform operations
else:
# None query result set retrieved
print("Query result is None")
API de grupo
El siguiente ejemplo de código obtiene todas las listas de la memoria caché que se han asociado con un grupo específico, Electrónica. El grupo se puede asociar usando DataTypeAttributes
clase durante la creación de la estructura de datos.
// List with this group already exists in cache
string groupName = "Electronics";
IDictionary<string, IDistributedList<Product>> result = cache.SearchService.GetGroupData<IDistributedList<Product>>(groupName);
if (result != null && result.Count > 0)
{
// Iterate over list
foreach (var item in result)
{
foreach (var i in item.Value)
{
// Perform operations
}
}
}
else
{
// No data against the group found
}
// Precondition: Cache is already connected
// List with this group already exists in the cache
String groupName = "Electronics";
Map<String, DistributedList<Product>> result = cache.getSearchService().getGroupData(groupName);
if (result != null && result.size() > 0) {
// Iterate over list
for (var item : result.entrySet()) {
// Perform operations
}
} else {
// No data against the group found
}
// This is an async method
// Precondition: Cache is already connected
// List with this group already exists in the cache
var groupName = "Electronics";
var result = await (
await this.cache.getSearchService()
).getGroupData(groupName);
if (result != null && result.size() > 0) {
// Iterate over list
for (var item in result.entrySet()) {
// Perform operations
}
} else {
// No data against the group found
}
# Precondition: Cache is already connected
# List with this group already exists in the cache
group_name = "Electronics"
result = cache.get_search_service().get_group_data(group_name)
if result is not None and len(result) > 0:
# Iterate over list
for item in result:
# Perform operations
print(item)
else:
# No data against the group found
print("No data found")
Note
Para garantizar que la operación sea a prueba de fallas, se recomienda manejar cualquier posible excepción dentro de su aplicación, como se explica en Manejo de fallas.
consulta SQL
El siguiente ejemplo de código obtiene los elementos de la memoria caché que se han asociado con una etiqueta específica, Acero Inoxidable. La etiqueta se puede asociar usando DataTypeAttributes
clase durante la creación de la estructura de datos.
// Items are already present in the cache with tags
// Custom class is query indexed through NCache Management Center or config.ncconf
// Search for items with tags
// Use the Fully Qualified Name (FQN) of your own custom class
string query = "Select $Value$ FROM FQN.Product WHERE $Tag$ = ?";
// Use QueryCommand for query execution
var queryCommand = new QueryCommand(query);
queryCommand.Parameters.Add("$Tag$", "Stainless Steel");
// Executing query
ICacheReader reader = cache.SearchService.ExecuteReader(queryCommand);
// Check if result set is not empty
if (reader.FieldCount > 0)
{
while (reader.Read())
{
// Get the value of the result set
Product result = reader.GetValue<Product>(1);
}
}
else
{
// Null query result set retrieved
}
// Pre-conditions: Cache is already connected
// Items are already present in the cache with tags
// Custom class is query indexed through NCache Management Center or config.ncconf
// Search for items with tags
// Use the Fully Qualified Name (FQN) of your own custom class
String query = "Select $Value$ FROM FQN.Product WHERE $Tag$ = ?";
// Use QueryCommand for query execution
var queryCommand = new QueryCommand(query);
queryCommand.getParameters().put("$Tag$", "Stainless Steel");
// Executing query
CacheReader reader = cache.getSearchService().executeReader(queryCommand);
// Check if result set is not empty
if (reader.getFieldCount() > 0) {
while (reader.read()) {
// Get the value of the result set
Product result = reader.getValue(1, Product.class);
}
} else {
// Null query result set retrieved
}
// This is an async method
// Pre-conditions: Cache is already connected
// Items are already present in the cache with tags
// Custom class is query indexed through NCache Management Center or config.ncconf
// Search for items with tags
// Use the Fully Qualified Name (FQN) of your own custom class
var query = "Select $Value$ FROM FQN.Product WHERE $Tag$ = ?";
// Use QueryCommand for query execution
var queryCommand = new ncache.QueryCommand(query);
var map = new Map();
var parameters = map.set("$Tag$", "Stainless Steel");
queryCommand.setParameters(parameters);
// Executing query
var searchService = await this.cache.getSearchService();
var reader = await searchService.executeReader(queryCommand);
// Check if result set is not empty
if (reader.getFieldCount() > 0) {
while (reader.read()) {
// Get the value of the result set
var result = reader.getValue(1, ncache.JsonDataType.Object);
// Perform operations
}
} else {
// Null query result set retrieved
}
# Pre-conditions: Cache is already connected
# Items are already present in the cache with tags
# Custom class is query indexed through NCache Management Center or config.ncconf
# Search for items with tags
# Use the Fully Qualified Name (FQN) of your own custom class
query = "Select $Value$ FROM FQN.Product WHERE $Tag$ = ?"
# Use QueryCommand for query execution
query_command = ncache.QueryCommand(query)
parameters = {"$Tag$": "Stainless Steel"}
query_command.set_parameters(parameters)
# Executing query
search_service = cache.get_search_service()
reader = search_service.execute_reader(query_command)
# Check if result set is not empty
if reader.get_field_count() > 0:
while reader.read():
# Get the value of the result set
result = reader.get_value(Product, 1)
# Perform operations
else:
# Null query result set retrieved
print("Query result is None")
API de etiquetas
El siguiente ejemplo de código recupera todas las instancias de diccionario de la memoria caché que se han asociado con una etiqueta específica, Acero Inoxidable. La etiqueta se puede asociar mediante el DataTypeAttributes
clase durante la creación de la estructura de datos.
// Items against this tag exist in cache
Tag tag = new Tag("Stainless Steel");
// Get dictionary against tag
IDictionary<string, IDistributedDictionary<string, Product>> result = cache.SearchService.GetByTag<IDistributedDictionary<string, Product>>(tag);
if (result != null && result.Count > 0)
{
foreach (var item in result)
{
// Perform operations
}
}
else
{
// Dictionary does not exist against tag
}
// Precondition: Cache is already connected
// Items against this tag already exist in the cache
Tag tag = new Tag("Stainless steel");
// Get map against tag
Map<String, DistributedMap<String, Product>> result = cache.getSearchService().getByTag(tag);
if (result != null && result.size() > 0) {
for (var item : result.entrySet()) {
// Perform operations
}
} else {
// Dictionary does not exist against tag
}
// This is an async method
// Precondition: Cache is already connected
// Items against this tag already exist in the cache
var tag = [new ncache.Tag("Stainless steel")];
// Get map against tag
var result = await (await this.cache.getSearchService()).getByTag(tag);
if (result != null && result.size() > 0) {
for (var item in result.entrySet()) {
// Perform operations
}
} else {
// Dictionary does not exist against tag
}
# Precondition: Cache is already connected
# Items against this tag already exist in the cache
tag = ncache.Tag("Stainless steel")
# Get map against tag
result = cache.get_search_service().get_by_tag(tag)
if result is not None and len(result) > 0:
for item in result:
# Perform operations
print(item)
else:
# Dictionary does not exist against tag
print("Dictionary not found")
NCache utiliza el $DataType$
palabra clave que buscará todas las estructuras de datos con la etiqueta con nombre especificada. El siguiente código asume que se ha agregado una lista con etiqueta con nombre El descuento con un valor 0.4 y lo obtiene mediante consultas.
// Data Structures exist with NamedTag Discount and value 0.4
// Create query
string query = "SELECT * FROM $DataType$ WHERE Discount = 0.4";
// Use QueryCommand for query execution
var queryCommand = new QueryCommand(query);
// Execute Query to search cache
ICacheReader queryResult = cache.SearchService.ExecuteReader(queryCommand);
// queryResult contains all the keys and metadata of result
if (queryResult.FieldCount > 0)
{
while (queryResult.Read())
{
// Key of list can be fetched through
queryResult.GetValue<DistributedList>(1);
}
}
else
{
// Null query result set retrieved
}
// Pre-conditions: Cache is already connected
// Data Structures exist with NamedTag "Discount" and value 0.4
// Create query
String query = "SELECT * FROM $DataType$ WHERE Discount = 0.4";
// Use QueryCommand for query execution
var queryCommand = new QueryCommand(query);
// Execute Query to search cache
CacheReader queryResult = cache.getSearchService().executeReader(queryCommand);
// queryResult contains all the keys and metadata of result
if (queryResult.getFieldCount() > 0) {
while (queryResult.read()) {
// Key of list can be fetched through
queryResult.getValue(0, DistributedList.class);
// Perform operations
}
} else {
// Null query result set retrieved
}
// This is an async method
// Pre-conditions: Cache is already connected
// Data Structures exist with NamedTag "Discount" and value 0.4
// Create query
var query = "SELECT * FROM $DataType$ WHERE Discount = 0.4";
// Use QueryCommand for query execution
var queryCommand = new ncache.QueryCommand(query);
// Execute Query to search cache
var searchService = await this.cache.getSearchService();
var queryResult = await searchService.executeReader(queryCommand);
// queryResult contains all the keys and metadata of result
if (queryResult.getFieldCount() > 0) {
while (queryResult.read()) {
// Key of list can be fetched through
queryResult.getValue(0, Number());
// Perform operations
}
} else {
// Null query result set retrieved
}
# Pre-conditions: Cache is already connected
# Data Structures exist with NamedTag "Discount" and value 0.4
# Create query
query = "SELECT * FROM $DataType$ WHERE discount = 0.4"
query_command = ncache.QueryCommand(query)
# Execute Query to search cache
search_service = cache.get_search_service()
query_result = search_service.execute_reader(query_command)
# queryResult contains all the keys and metadata of result
if query_result.get_field_count() > 0:
while query_result.read():
# Key of list can be fetched through
query_result.get_value(int, 1)
# Perform operations
else:
# No data containing the named tag(s) exist
print("Data not found")
Recursos adicionales
NCache proporciona una aplicación de muestra para consultar estructuras de datos en GitHub.
Vea también
.NETO: Alachisoft.NCache.Client.Tipos de datos espacio de nombres
Java: com.alachisoft.ncache.cliente.estructuras de datos espacio de nombres
Nodo.js: Administrador de estructuras de datos clase.
Pitón: ncache.cliente.estructuras de datos clase.