Posts (page 4)
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4 min readIn Solr, collection names must be unique within a Solr cluster. They cannot contain spaces, special characters, or punctuation marks except for underscore (_) and hyphen (-). Collection names should also not exceed 256 characters in length. Additionally, it is recommended to avoid using reserved keywords or words with special meanings in Solr as collection names to prevent any potential conflicts or errors.
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6 min readTo set "seen:true" in an array of messages in Mongoose, you can use the update method to update the messages array in your document. You can use the $set operator to set the "seen" field to true for all the messages in the array. Here's an example of how you can achieve this: YourModel.findByIdAndUpdate( { _id: yourDocumentId }, { $set: { "messages.$[].seen": true } }, function(err, result) { if (err) { console.log(err); } else { console.
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7 min readTo get a TTL (Time-To-Live) or expired document in MongoDB, you can use the expireAfterSeconds index option in a collection. This option allows you to specify a field in your documents that determines when they will expire. Once the TTL index is created, MongoDB will automatically delete documents that have passed their expiration time. You can set the expiration time by providing a value in seconds when creating the index.
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5 min readTo search nested properties in Elasticsearch, you can use the dot notation to access the nested fields. For example, if you have a nested field called "nestedField" with subfields "subField1" and "subField2", you can search for documents where subField1 equals a specific value by using the query "nestedField.subField1:value". This allows you to access and query nested properties within your Elasticsearch documents.
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4 min readIn MongoDB, you can combine or aggregate column lists using the $project operator in the aggregation pipeline. This operator allows you to reshape documents by including, excluding, or adding new fields based on existing fields.To combine column lists in MongoDB, you can use the $project operator with the $concat operator to concatenate multiple fields together.
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8 min readDynamoDB and ScyllaDB are both NoSQL databases, but they have some key differences.DynamoDB is a fully managed cloud-based database service provided by Amazon Web Services (AWS). It is a key-value and document database that is designed for high availability, scalability, and low latency. DynamoDB is known for its seamless integration with other AWS services and its ability to handle massive amounts of data with ease.
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4 min readTo replace only one object from an array in MongoDB, you can use the $ operator to update the specific element in the array. This operator allows you to reference the element you want to replace by its index position within the array.For example, if you have a collection with an array field called "items" and you want to replace the object at index 2 with a new object, you can use the following query:db.collection.update( {}, { $set: { "items.
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4 min readTo create a pipeline in MongoDB to group and count data, you can use the aggregation framework. The aggregation framework allows you to process data and perform various operations, such as grouping and counting, on documents in a MongoDB collection.To create a pipeline for grouping and counting, you can use the $group stage in the aggregation pipeline.
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6 min readTo find unique values from an array of objects in MongoDB, you can use the aggregation framework. One common approach is to use the $unwind operator to deconstruct the array into individual documents, then use the $group operator to group documents by the desired field and use the $addToSet operator to create a set of unique values. Finally, you can use the $project operator to reshape the output if needed. This will allow you to find unique values from an array of objects in MongoDB.
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7 min readTo find an array and a specific value for a field in Mongoose, you can use the find() method with a query parameter. You can specify the field you want to search for and the value you are looking for in the query object. For example, if you want to find an array of documents where the field name has a specific value of John, you can do the following: Model.find({ name: 'John' }, (err, result) => { if (err) { console.log(err); } else { console.
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5 min readTo limit text score with the $gt operator in MongoDB, you can use the $text operator along with the $meta projection operator to limit the documents based on their text score. By specifying a minimum threshold for the text score using the $gt operator, you can exclude documents that do not meet the specified score criteria. This allows you to filter out documents that have lower text relevancy or quality in your search results.
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5 min readTo filter list values in DynamoDB, you can use the CONTAINS condition in a Query or Scan operation to check if a list attribute contains a specific value. This can be used to filter the results based on the presence of a particular value in a list attribute. Additionally, you can also use the NOT_CONTAINS condition to filter out items that do not contain a specific value in the list attribute.