Removing Duplicates
Removing duplicates is the process of identifying and deleting repeated entries in a dataset. The various data deduplication methods are:
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SQL Commands: For example, you can use the SELECT DISTINCT command in SQL to retrieve only unique records from a dataset.
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Data Cleaning Tools: Programs like Excel or Python libraries (e.g., Pandas) supports deduplication with built-in functions to detect and eliminate duplicate entries.
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Manual Review: For small datasets, you can review records manually to identify and delete duplicates.
Deduplication is performed during the transformation phase of data processing, especially when merging data sources, preparing for storage, or ensuring clean data for analysis. For example, duplicate loan repayment records in a report could inflate the numbers, leading to misleading conclusions. However, in some cases duplicates should not always be removed, for example, in system logs, duplicates may indicate repeated events or actions that are essential for tracking.