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Utilizzalo BatchExecuteStatement con un AWS SDK
Gli esempi di codice seguenti mostrano come utilizzare BatchExecuteStatement.
Gli esempi di operazioni sono estratti di codice da programmi più grandi e devono essere eseguiti nel contesto. È possibile visualizzare questa operazione nel contesto nel seguente esempio di codice:
- AWS SDK for .NET
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Nota
C'è altro da fare. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS
. Utilizzo di batch di istruzioni INSERT per aggiungere elementi.
/// <summary> /// Inserts movies imported from a JSON file into the movie table by /// using an Amazon DynamoDB PartiQL INSERT statement. /// </summary> /// <param name="tableName">The name of the table into which the movie /// information will be inserted.</param> /// <param name="movieFileName">The name of the JSON file that contains /// movie information.</param> /// <returns>A Boolean value that indicates the success or failure of /// the insert operation.</returns> public static async Task<bool> InsertMovies(string tableName, string movieFileName) { // Get the list of movies from the JSON file. var movies = ImportMovies(movieFileName); var success = false; if (movies is not null) { // Insert the movies in a batch using PartiQL. Because the // batch can contain a maximum of 25 items, insert 25 movies // at a time. string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}"; var statements = new List<BatchStatementRequest>(); try { for (var indexOffset = 0; indexOffset < 250; indexOffset += 25) { for (var i = indexOffset; i < indexOffset + 25; i++) { statements.Add(new BatchStatementRequest { Statement = insertBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = movies[i].Title }, new AttributeValue { N = movies[i].Year.ToString() }, }, }); } var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest { Statements = statements, }); // Wait between batches for movies to be successfully added. System.Threading.Thread.Sleep(3000); success = response.HttpStatusCode == System.Net.HttpStatusCode.OK; // Clear the list of statements for the next batch. statements.Clear(); } } catch (AmazonDynamoDBException ex) { Console.WriteLine(ex.Message); } } return success; } /// <summary> /// Loads the contents of a JSON file into a list of movies to be /// added to the DynamoDB table. /// </summary> /// <param name="movieFileName">The full path to the JSON file.</param> /// <returns>A generic list of movie objects.</returns> public static List<Movie> ImportMovies(string movieFileName) { if (!File.Exists(movieFileName)) { return null!; } using var sr = new StreamReader(movieFileName); string json = sr.ReadToEnd(); var allMovies = JsonConvert.DeserializeObject<List<Movie>>(json); if (allMovies is not null) { // Return the first 250 entries. return allMovies.GetRange(0, 250); } else { return null!; } }Utilizzo di batch di istruzioni SELECT per ottenere elementi.
/// <summary> /// Gets movies from the movie table by /// using an Amazon DynamoDB PartiQL SELECT statement. /// </summary> /// <param name="tableName">The name of the table.</param> /// <param name="title1">The title of the first movie.</param> /// <param name="title2">The title of the second movie.</param> /// <param name="year1">The year of the first movie.</param> /// <param name="year2">The year of the second movie.</param> /// <returns>True if successful.</returns> public static async Task<bool> GetBatch( string tableName, string title1, string title2, int year1, int year2) { var getBatch = $"SELECT FROM {tableName} WHERE title = ? AND year = ?"; var statements = new List<BatchStatementRequest> { new BatchStatementRequest { Statement = getBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = title1 }, new AttributeValue { N = year1.ToString() }, }, }, new BatchStatementRequest { Statement = getBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = title2 }, new AttributeValue { N = year2.ToString() }, }, } }; var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest { Statements = statements, }); if (response.Responses.Count > 0) { response.Responses.ForEach(r => { Console.WriteLine($"{r.Item["title"]}\t{r.Item["year"]}"); }); return true; } else { Console.WriteLine($"Couldn't find either {title1} or {title2}."); return false; } }Utilizzo di batch di istruzioni UPDATE per aggiornare elementi.
/// <summary> /// Updates information for multiple movies. /// </summary> /// <param name="tableName">The name of the table containing the /// movies to be updated.</param> /// <param name="producer1">The producer name for the first movie /// to update.</param> /// <param name="title1">The title of the first movie.</param> /// <param name="year1">The year that the first movie was released.</param> /// <param name="producer2">The producer name for the second /// movie to update.</param> /// <param name="title2">The title of the second movie.</param> /// <param name="year2">The year that the second movie was released.</param> /// <returns>A Boolean value that indicates the success of the update.</returns> public static async Task<bool> UpdateBatch( string tableName, string producer1, string title1, int year1, string producer2, string title2, int year2) { string updateBatch = $"UPDATE {tableName} SET Producer=? WHERE title = ? AND year = ?"; var statements = new List<BatchStatementRequest> { new BatchStatementRequest { Statement = updateBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = producer1 }, new AttributeValue { S = title1 }, new AttributeValue { N = year1.ToString() }, }, }, new BatchStatementRequest { Statement = updateBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = producer2 }, new AttributeValue { S = title2 }, new AttributeValue { N = year2.ToString() }, }, } }; var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest { Statements = statements, }); return response.HttpStatusCode == System.Net.HttpStatusCode.OK; }Utilizzo di batch di istruzioni DELETE per eliminare elementi.
/// <summary> /// Deletes multiple movies using a PartiQL BatchExecuteAsync /// statement. /// </summary> /// <param name="tableName">The name of the table containing the /// moves that will be deleted.</param> /// <param name="title1">The title of the first movie.</param> /// <param name="year1">The year the first movie was released.</param> /// <param name="title2">The title of the second movie.</param> /// <param name="year2">The year the second movie was released.</param> /// <returns>A Boolean value indicating the success of the operation.</returns> public static async Task<bool> DeleteBatch( string tableName, string title1, int year1, string title2, int year2) { string updateBatch = $"DELETE FROM {tableName} WHERE title = ? AND year = ?"; var statements = new List<BatchStatementRequest> { new BatchStatementRequest { Statement = updateBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = title1 }, new AttributeValue { N = year1.ToString() }, }, }, new BatchStatementRequest { Statement = updateBatch, Parameters = new List<AttributeValue> { new AttributeValue { S = title2 }, new AttributeValue { N = year2.ToString() }, }, } }; var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest { Statements = statements, }); return response.HttpStatusCode == System.Net.HttpStatusCode.OK; }-
Per i dettagli sull'API, consulta la BatchExecuteStatementsezione AWS SDK for .NET API Reference.
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