Represents a set of primary keys and, for each key, the attributes to retrieve from the table.

Пример #1
0
        public void BatchSamples()
        {
            EnsureTables();

            {
                #region BatchGet Sample 1

                // Define attributes to get and keys to retrieve
                List<string> attributesToGet = new List<string> { "Author", "Title", "Year" };
                List<Dictionary<string, AttributeValue>> sampleTableKeys = new List<Dictionary<string, AttributeValue>>
                {
                    new Dictionary<string, AttributeValue>
                    {
                        { "Author", new AttributeValue { S = "Mark Twain" } },
                        { "Title", new AttributeValue { S = "The Adventures of Tom Sawyer" } }
                    },
                    new Dictionary<string, AttributeValue>
                    {
                        { "Author", new AttributeValue { S = "Mark Twain" } },
                        { "Title", new AttributeValue { S = "Adventures of Huckleberry Finn" } }
                    }
                };

                // Construct get-request for first table
                KeysAndAttributes sampleTableItems = new KeysAndAttributes
                {
                    AttributesToGet = attributesToGet,
                    Keys = sampleTableKeys
                };

                #endregion

                #region BatchGet Sample 2

                // Define keys to retrieve
                List<Dictionary<string, AttributeValue>> authorsTableKeys = new List<Dictionary<string, AttributeValue>>
                {
                    new Dictionary<string, AttributeValue>
                    {
                        { "Author", new AttributeValue { S = "Mark Twain" } },
                    },
                    new Dictionary<string, AttributeValue>
                    {
                        { "Author", new AttributeValue { S = "Booker Taliaferro Washington" } },
                    }
                };

                // Construct get-request for second table
                //  Skip setting AttributesToGet property to retrieve all attributes
                KeysAndAttributes authorsTableItems = new KeysAndAttributes
                {
                    Keys = authorsTableKeys,
                };

                #endregion

                #region BatchGet Sample 3

                // Create a client
                AmazonDynamoDBClient client = new AmazonDynamoDBClient();

                // Construct table-keys mapping
                Dictionary<string, KeysAndAttributes> requestItems = new Dictionary<string, KeysAndAttributes>();
                requestItems["SampleTable"] = sampleTableItems;
                requestItems["AuthorsTable"] = authorsTableItems;

                // Construct request
                BatchGetItemRequest request = new BatchGetItemRequest
                {
                    RequestItems = requestItems
                };

                BatchGetItemResult result;
                do
                {
                    // Issue request and retrieve items
                    result = client.BatchGetItem(request);

                    // Iterate through responses
                    Dictionary<string, List<Dictionary<string, AttributeValue>>> responses = result.Responses;
                    foreach (string tableName in responses.Keys)
                    {
                        // Get items for each table
                        List<Dictionary<string, AttributeValue>> tableItems = responses[tableName];

                        // View items
                        foreach (Dictionary<string, AttributeValue> item in tableItems)
                        {
                            Console.WriteLine("Item:");
                            foreach (var keyValuePair in item)
                            {
                                Console.WriteLine("{0} : S={1}, N={2}, SS=[{3}], NS=[{4}]",
                                    keyValuePair.Key,
                                    keyValuePair.Value.S,
                                    keyValuePair.Value.N,
                                    string.Join(", ", keyValuePair.Value.SS ?? new List<string>()),
                                    string.Join(", ", keyValuePair.Value.NS ?? new List<string>()));
                            }
                        }
                    }

                    // Some items may not have been retrieved!
                    //  Set RequestItems to the result's UnprocessedKeys and reissue request
                    request.RequestItems = result.UnprocessedKeys;

                } while (result.UnprocessedKeys.Count > 0);

                #endregion
            }


            {
                #region BatchWrite Sample 1

                // Create items to put into first table
                Dictionary<string, AttributeValue> item1 = new Dictionary<string, AttributeValue>();
                item1["Author"] = new AttributeValue { S = "Mark Twain" };
                item1["Title"] = new AttributeValue { S = "A Connecticut Yankee in King Arthur's Court" };
                item1["Pages"] = new AttributeValue { N = "575" };
                Dictionary<string, AttributeValue> item2 = new Dictionary<string, AttributeValue>();
                item2["Author"] = new AttributeValue { S = "Booker Taliaferro Washington" };
                item2["Title"] = new AttributeValue { S = "My Larger Education" };
                item2["Pages"] = new AttributeValue { N = "313" };
                item2["Year"] = new AttributeValue { N = "1911" };

                // Create key for item to delete from first table
                //  Hash-key of the target item is string value "Mark Twain"
                //  Range-key of the target item is string value "Tom Sawyer, Detective"
                Dictionary<string, AttributeValue> keyToDelete1 = new Dictionary<string, AttributeValue>
                {
                    { "Author", new AttributeValue { S = "Mark Twain" } },
                    { "Title", new AttributeValue { S = "Tom Sawyer, Detective" } }
                };

                // Construct write-request for first table
                List<WriteRequest> sampleTableItems = new List<WriteRequest>();
                sampleTableItems.Add(new WriteRequest
                {
                    PutRequest = new PutRequest { Item = item1 }
                });
                sampleTableItems.Add(new WriteRequest
                {
                    PutRequest = new PutRequest { Item = item2 }
                });
                sampleTableItems.Add(new WriteRequest
                {
                    DeleteRequest = new DeleteRequest { Key = keyToDelete1 }
                });

                #endregion

                #region BatchWrite Sample 2

                // Create key for item to delete from second table
                //  Hash-key of the target item is string value "Francis Scott Key Fitzgerald"
                Dictionary<string, AttributeValue> keyToDelete2 = new Dictionary<string, AttributeValue>
                {
                    { "Author", new AttributeValue { S = "Francis Scott Key Fitzgerald" } },
                };

                // Construct write-request for first table
                List<WriteRequest> authorsTableItems = new List<WriteRequest>();
                authorsTableItems.Add(new WriteRequest
                {
                    DeleteRequest = new DeleteRequest { Key = keyToDelete2 }
                });

                #endregion

                #region BatchWrite Sample 3

                // Create a client
                AmazonDynamoDBClient client = new AmazonDynamoDBClient();

                // Construct table-keys mapping
                Dictionary<string, List<WriteRequest>> requestItems = new Dictionary<string, List<WriteRequest>>();
                requestItems["SampleTable"] = sampleTableItems;
                requestItems["AuthorsTable"] = authorsTableItems;

                BatchWriteItemRequest request = new BatchWriteItemRequest { RequestItems = requestItems };
                BatchWriteItemResult result;
                do
                {
                    // Issue request and retrieve items
                    result = client.BatchWriteItem(request);

                    // Some items may not have been processed!
                    //  Set RequestItems to the result's UnprocessedItems and reissue request
                    request.RequestItems = result.UnprocessedItems;

                } while (result.UnprocessedItems.Count > 0);

                #endregion
            }
        }