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databases

Database management and optimization

DatabasesFind SQL Duplicates by Email & Name: GROUP BY Guide

Learn to find and remove SQL duplicates by multiple fields like email and name using GROUP BY, HAVING, window functions. Examples for detecting, retrieving full rows, and safe deletion in MySQL, PostgreSQL, SQL Server.

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DatabasesSet SQLite WAL Mode in Python 3.12 with autocommit=False

Fix OperationalError when setting SQLite journal_mode to WAL in Python 3.12 sqlite3.connect(autocommit=False). Commit implicit transaction first or use persistent WAL setup for sqlite3 python apps.

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DatabasesUnderstanding MySQL Index Types: PRIMARY, UNIQUE, FULLTEXT

Learn the key differences between PRIMARY, UNIQUE, INDEX, and FULLTEXT index types in MySQL. Discover when to use each type for optimal database performance and design.

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DatabasesOracle SQL: Get Max Date Row Per UserId (Latest Record)

Learn Oracle SQL techniques to fetch rows with maximum Date per UserId. Use ROW_NUMBER window function, JOIN subquery, NOT EXISTS, or KEEP DENSE_RANK for latest records efficiently on large tables.

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DatabasesSQLAlchemy Order By Desc: How to Sort Descending

Fix NameError in SQLAlchemy order_by() for descending sort. Use desc() import or column.desc() to ORDER BY amount DESC with joins and filters. Complete examples for sql alchemy queries.

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DatabasesIs WAL Redundant for Append-Only Time-Series TSDB?

Discover why WAL isn't redundant in append-only TSDBs. Learn flaws in data file reasoning, failure modes like power loss, crash recovery benefits, and real-world examples from QuestDB, SQLite for durability and replication.

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ProgrammingConvert Chrono DateTime to BSON in Rust MongoDB 3.4.1

Fix 'expected DateTime, found DateTime' error converting chrono::DateTime to BSON DateTime in Rust with mongodb 3.4.1. Add bson crate with chrono-0_4, use from_chrono() or Into for rust chrono, rust mongodb serialization.

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DatabasesTrigger SQLAlchemy onupdate for Bulk Updates & setattr

Learn why SQLAlchemy mapped_column onupdate=func.now() doesn't trigger with setattr or bulk updates. Fix automatic timestamp updates in ORM, bulk_update_mappings, and Query.update with code examples and best practices.

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DatabasesSQL Subquery Derived Table: Select All Sale Columns

Learn to use an SQL subquery as a derived table to select all columns from the Sale table for female customers (Gender='F'). Fix your query with INNER JOIN and DISTINCT for perfect results.

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DatabasesLade.io Managed PostgreSQL Hosting: Reliable Review

Explore Lade.io as a managed PostgreSQL hosting provider. Compare reliability, backups, scaling, HA with AWS RDS, Supabase, Render. Real experiences, uptime, performance for production databases.

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DatabasesPolarDB IMCI: Optimize SELECT * on Wide Tables

Mitigate read amplification for SELECT * on wide tables (500+ columns) in PolarDB IMCI. Column pruning, optimizer settings, and hybrid execution tips.

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DatabasesMySQL JDBC Connection Refused Error: Troubleshooting Guide

Troubleshoot MySQL JDBC connection refused errors when command-line MySQL works. Learn about bind-address, IPv6/IPv4 conflicts, firewall issues, and solutions.

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DatabasesEssential Data Quality Checks for Analytics Dashboards

Comprehensive guide to data quality checks, validation techniques, and thresholds for reliable analytics dashboards. Learn how to ensure data reliability before publishing.

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DatabasesExtract JSON Nodes from OpenSearch with Mustache Templates

Learn how to extract specific inner JSON nodes from OpenSearch data using Mustache templates. Efficiently retrieve nested 'clientAccounts' data without returning entire documents.

1 answer• 1 view