Understanding the UPDATE RETURNING Clause’s Incremental Data Visibility Issue Overview: RETURNING Clause Reflects Intermediate Row States During Bulk Updates The core issue arises when using the UPDATE … RETURNING syntax in SQLite to modify multiple rows and return computed results based on the updated state of the database. Users expect the RETURNING clause to evaluate…
Floating-Point Inaccuracy in log10(100.0) During func7-pg-181 Test The func7-pg-181 test in SQLite’s test suite fails on x86 32-bit systems when calculating log10(100.0) with a formatted output of %.30f. The test expects the result 2.000000000000000000000000000000, but on 32-bit x86 architectures, the actual result is 1.999999999999999000000000000000. This discrepancy arises from differences in floating-point precision handling between architectures…
Issue Overview: Views with Mixed Column Types in SQLite 3.41 In SQLite 3.41, a significant change was introduced regarding how views handle columns with mixed data types across tables. This change affects the behavior of views that are constructed using compound SELECT statements, such as UNION ALL, when the underlying tables have columns with different…
Managing Large-Scale Data Storage: Single Database vs. Attached Databases and Binary Files The core challenge revolves around determining the optimal strategy for storing large volumes of binary data (e.g., simulation outputs, images, documents) using SQLite. The debate centers on three architectural approaches: Single large SQLite database storing all binary data as BLOBs. Multiple smaller SQLite…
Issue Overview: SQLITE_CORRUPT Error When Querying Tables Exceeding 2000 Columns via Python The core problem arises when attempting to interact with SQLite tables containing more than 2000 columns through Python’s sqlite3 driver. Despite recompiling the SQLite engine with -DSQLITE_MAX_COLUMN=32767 to raise the column limit, users encounter a malformed schema error: [SQLITE_CORRUPT] The database disk image…
Issue Overview: SQLite substr() Function Behavior with Zero Index and Non-Standard Arguments The SQLite substr() function is designed to extract a substring from a given string based on a starting position (index) and an optional length. However, the behavior of this function becomes ambiguous and potentially misleading when certain non-standard or undefined arguments are passed,…
Understanding the "Attempt to Write a Readonly Database" Error in SQLite The error message "Attempt to write a readonly database" (SQLite error code 0x800017FF) is a common issue encountered by developers and users working with SQLite databases, particularly on Windows 10. This error occurs when an application attempts to perform a write operation (such as…
Issue Overview: strftime Calculation in SQLite Queries When working with SQLite, understanding how and when functions like strftime are evaluated is crucial for optimizing query performance. The core issue revolves around whether the strftime function, when used in a query, is calculated once for the entire query or repeatedly for each row processed. This distinction…
HEX Function Output Cannot Be Directly Converted Back to Original Data Type The core issue revolves around reversing the output of SQLite’s HEX() function to retrieve the original value. Users discovered that while HEX() converts input (text, integers, blobs) into a hexadecimal string representation, there is no built-in inverse function (UNHEX()) in SQLite versions prior…
Issue Overview: Round() Function Precision and Output Formatting in SQLite The core issue revolves around the behavior of the round() function in SQLite, specifically how it handles precision and formatting of floating-point numbers. Users expect the round(X, Y) function to round the number X to Y decimal places and display the result with exactly Y…