Documents

Here-Documents and Here-Strings

Learn how to feed multi-line literal text into commands using heredocs (<<) and here-strings (<<<), including quoting rules and indentation control.

Elasticsearch with Kibana

How Kibana pairs with Elasticsearch as the visualization, exploration, and management layer of the Elastic Stack.

Indices, Documents, and Mappings

How Elasticsearch organizes data into indices and documents, and how mappings define the field types that control indexing and search behavior.

Nested Aggregations

Learn how the nested and reverse_nested aggregations let Elasticsearch correctly aggregate over arrays of objects mapped with the nested field type.

Deleting Documents

Learn how to remove documents from MongoDB collections with deleteOne and deleteMany, and how to safely drop entire collections.

Documents and Collections

How MongoDB structures data into documents and collections, including field types, embedding versus referencing, and the _id field.

Inserting Documents

Learn how to add data to MongoDB collections with insertOne and insertMany, how _id is generated, and how schema flexibility affects inserts.

Querying Documents

Learn how to retrieve documents from MongoDB collections using find() and findOne(), filters, projections, and cursor methods.

The Aggregation Pipeline

Learn how MongoDB's aggregation pipeline transforms documents through an ordered sequence of stages to filter, reshape, and summarize data.

Updating Documents

Learn how to modify existing documents using updateOne, updateMany, replaceOne, update operators like $set and $inc, and upserts.

Working with Arrays and Nested Documents

Master querying and updating deeply nested MongoDB documents and arrays using dot notation, positional operators, and array update operators.

LlamaIndex Cheat Sheet

Ingest, index, and query your own data for LLM apps using LlamaIndex's data connectors, indices, retrievers, and query engines.