Autosave: 2024-06-23 19:15:05

zk/DynamoDB CLI commands.md

@@ -1,72 +0,0 @@
----
-id: l045
-title: DynamoDB CLI commands
-tags: [AWS, databases, dynamodb]
-created: Saturday, June 22, 2024
----
-
-# DynamoDB CLI commands
-
-## Connecting to a local (Docker)/prod (AWS) DynamoDB instance
-
-In order to distinguish between local and production accounts you should keep
-seperate profiles for each (via `.aws/config` and `.aws/credentials`).
-
-When connecting to a local DB use the local profile and the local URL. Without
-the `--profile` flag, AWS will default to the `default` profile which will
-typically be your credentials for accessing AWS on the remote.
-
-It also sometimes required to add the endpoint-url when working locally:
-
-```
---endpoint-url http://localhost:800
-
-> When using the commans below locally, assume `--endpoint-url` and `--profile`
-> have been appended
-
-```
-
-For example:
-
-```sh
-aws dynamodb list-tables \
---profile timetracking_dev \
---endpoint-url http://localhost:800
-```
-
-## Delete a table
-
-```sh
-aws dynamodb delete-table \
---table-name TableName
-```
-
-## Create table from JSON schema
-
-```sh
-aws dynamodb create-table \
---cli-input-json file://create-timeentries-table.json \
-
-```
-
-## Describe the table
-
-View the table schema:
-
-```sh
-
-aws dynamodb describe-table \
---table-name TimeEntries
-```
-
-## Scan the table
-
-```sh
-aws dynamodb scan \
---table-name TimeEntries \
---output table
-
-
-```
-
-## Related notes

zk/DynamoDB SDK commands.md

@@ -1,64 +0,0 @@
----
-id: 8b6h
-title: DynamoDB SDK commands
-tags: [AWS, databases, dynamodb]
-created: Sunday, June 23, 2024
----
-
-# DynamoDB SDK commands
-
-The following commands are for using `@aws-sdk/client-dynamodb` (the JS SDK).
-
-## Create client
-
-```js
-import DynamoDBClient from "@aws-sdk/client-dynamodb";
-
-const client = new DynamoDBClient({
-  region: "eu-west-2",
-  accessKeyId: process.env.ACCESS_KEY_ID,
-  secretAccessKey: process.env.ACCESS_KEY_ID,
-});
-```
-
-### DynamoDB Document Client
-
-The Document Client returns the data as a standard JSON document in the manner
-of a document-based NoSQL database. Without it, DynamoDB will return the data
-with type data which is unwieldy and hard to parse.
-
-To transform into a document structure:
-
-```js
-import DynamoDBClient from "@aws-sdk/client-dynamodb";
-import DynamoDBDocumentClient from "@aws-sdk/lib-dynamodb";
-
-const client = new DynamoDBClient({
-  region: "eu-west-2",
-  accessKeyId: process.env.ACCESS_KEY_ID,
-  secretAccessKey: process.env.ACCESS_KEY_ID,
-});
-
-const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
-```
-
-## Query a table
-
-Querying is the most performant and cost-effective method since it is an O(1)
-lookup against a partition key or secondary index.
-
-```js
-const params = {
-  TableName: "YourTableName",
-  KeyConditionExpression: "#pk = :pk",
-  ExpressionAttributeNames: { "#pk": "PrimaryKeyAttributeName" },
-  ExpressionAttributeValues: { ":pk": "PrimaryKeyValue" },
-};
-```
-
-## Scan a table
-
-Scanning is less performant (O(n)) and most expensive since it requires checking
-every item in the database.
-
-## Related notes

zk/DynamoDB_CLI_commands.md

@@ -16,6 +16,16 @@ When connecting to a local DB use the local profile and the local URL. Without
 the `--profile` flag, AWS will default to the `default` profile which will
 typically be your credentials for accessing AWS on the remote.
 
+It also sometimes required to add the endpoint-url when working locally:
+
+```
+--endpoint-url http://localhost:800
+
+> When using the commans below locally, assume `--endpoint-url` and `--profile`
+> have been appended
+
+```
+
 For example:
 
 ```sh
@@ -28,8 +38,6 @@ aws dynamodb list-tables \
 
 ```sh
 aws dynamodb delete-table \
---profile timetracking_dev \
---endpoint-url http://localhost:8000 \
 --table-name TableName
 ```
 
@@ -38,9 +46,25 @@ aws dynamodb delete-table \
 ```sh
 aws dynamodb create-table \
 --cli-input-json file://create-timeentries-table.json \
---profile timetracking_dev \
---endpoint-url http://localhost:8000
 
 ```
 
+## Describe the table
+
+View the table schema:
+
+```sh
+
+aws dynamodb describe-table \
+--table-name TimeEntries
+```
+
+## Scan the table
+
+```sh
+aws dynamodb scan \
+--table-name TimeEntries \
+--output table
+```
+
 ## Related notes

zk/DynamoDB_SDK_commands.md

@@ -7,16 +7,75 @@ created: Sunday, June 23, 2024
 
 # DynamoDB SDK commands
 
-The following commands are for using `$aws-sdk/client-dynamodb` (the JS SDK).
+The following commands are for using `@aws-sdk/client-dynamodb` (the JS SDK).
 
 ## Create client
 
 ```js
-const params = {
+import DynamoDBClient from "@aws-sdk/client-dynamodb";
+
+const client = new DynamoDBClient({
   region: "eu-west-2",
   accessKeyId: process.env.ACCESS_KEY_ID,
   secretAccessKey: process.env.ACCESS_KEY_ID,
+});
+```
+
+### DynamoDB Document Client
+
+The Document Client returns the data as a standard JSON document in the manner
+of a document-based NoSQL database. Without it, DynamoDB will return the data
+with type data which is unwieldy and hard to parse.
+
+To transform into a document structure:
+
+```js
+import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
+import { DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb";
+
+const client = new DynamoDBClient({
+  region: "eu-west-2",
+  accessKeyId: process.env.ACCESS_KEY_ID,
+  secretAccessKey: process.env.ACCESS_KEY_ID,
+});
+
+const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
+```
+
+## Query a table
+
+Querying is the most performant and cost-effective method since it is an O(1)
+lookup against a partition key or secondary index.
+
+```js
+import { DynamoDBDocumentClient, QueryCommand } from "@aws-sdk/lib-dynamodb";
+
+const params = {
+  TableName: "YourTableName",
+  KeyConditionExpression: "#pk = :pk",
+  ExpressionAttributeNames: { "#pk": "PrimaryKeyAttributeName" },
+  ExpressionAttributeValues: { ":pk": "PrimaryKeyValue" },
 };
+
+const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
+const data = await dynamoDbDocumentClient.send(new QueryCommand(params));
+console.log(data);
+```
+
+## Scan a table
+
+Scanning is less performant (O(n)) and most expensive since it requires checking
+every item in the database.
+
+```js
+import { DynamoDBDocumentClient, ScanCommand } from "@aws-sdk/lib-dynamodb";
+
+const params = {
+  TableName: "YourTableName",
+};
+
+const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
+const data = await dynamoDbDocumentClient.send(new ScanCommand(params));
 ```
 
 ## Related notes

zk/Integrated_circuits.md

@@ -7,8 +7,7 @@ tags:
 # Integrated circuits
 
 An integrated circuit (IC) is a single unit that comprises several logic gates
-designed for the easy construction of
+designed for the easy construction of [digital circuits](Digital_circuits.md).
-[digital circuits](Digital_circuits.md).
 The terms "integrated circuit" and "chip" are often used interchangeably.
 
 An IC puts the gates on a single piece of silicon that has electrical contact
@@ -24,5 +23,6 @@ to a breadboard.
 
 _An integrated circuit and its use on a breadboard:_
 
-<img align="left" width="200" src="/home/thomas/repos/computer_science/img/integrated-circuit.jpeg">
+![](../img/integrated-circuit.jpeg)
-<img  width="200" src="/home/thomas/repos/computer_science/img/breadboard-DIP.jpg">
+
+![](../img/breadboard-DIP.jpg)

zk/LEDs.md

@@ -21,5 +21,5 @@ generic diode circuit symbol:
 An LED diode lights up when the right amount of current flows through it. A
 standard LED has a maximum current of 20mA. An appropriate
 [resistor](Resistance.md#resistors)
-must therefore be added to the circuit to ensure the current doesn't exeedd this
+must therefore be added to the circuit to ensure the current doesn't exceed this
 amount.