Issue Overview: Silent Success When Updating Non-Existing Rows In SQLite, executing an UPDATE statement on a table where the WHERE clause does not match any rows does not result in an error. Instead, the operation completes successfully without modifying any data. This behavior can be surprising, especially for developers coming from a procedural programming background,…
SQLite Batch Atomic Writes: File System Compatibility and Performance Considerations Issue Overview SQLite’s SQLITE_ENABLE_BATCH_ATOMIC_WRITE feature is a powerful optimization that allows multiple writes to be grouped into a single atomic operation, significantly improving performance and ensuring data integrity. However, this feature is not universally supported across all file systems. The primary challenge lies in identifying…
Filename Encoding Constraints in SQLite: Technical Foundations and Observed Behavior Core Conflict Between SQLite Documentation and Filesystem Practices The central issue revolves around SQLite’s documented requirement that filenames passed to sqlite3_open() and related functions must be UTF-8 or UTF-16 encoded. This conflicts with Unix-family operating systems’ historical treatment of filenames as raw octet sequences, where…
Issue Overview: ALTER TABLE Integrity Check False Positive on REAL Default Values When attempting to add a new column with a NOT NULL constraint and a DEFAULT value of REAL affinity (e.g., DEFAULT .25) via ALTER TABLE, SQLite versions 3.42.0 through 3.46.0 may throw a "Runtime error: NOT NULL constraint failed" despite valid schema modifications….
Understanding the Overflow_const Warning in SQLite’s renameParseSql Function The overflow_const warning reported by Coverity in the SQLite function renameParseSql highlights a potential integer overflow scenario. This warning arises when the static analysis tool detects that a value being assigned to an 8-bit unsigned integer could exceed its maximum capacity, leading to undefined behavior or incorrect…
Understanding the UPSERT and RETURNING Clause Interaction in SQLite The UPSERT operation in SQLite is a powerful feature that combines the functionality of INSERT and UPDATE into a single statement. It allows you to insert a new row into a table if it does not already exist, or update the existing row if a conflict…
Invalid Foreign Key Reference to Non-Primary Key Column The core issue arises when attempting to create a foreign key relationship between a column in a child table and a column in a parent table that is neither a primary key nor part of a unique constraint. In the provided schema, Table 3 ("testsheet_pe_3_swgrParams" or simplified…
Understanding the Problem: Identifying Generated Columns in SQLite The core issue revolves around the need to distinguish between regular columns and generated columns in SQLite when using the pragma_table_xinfo() function. Generated columns, which are computed based on other columns in the table, can cause complications during operations like INSERT INTO … SELECT * FROM ……
Understanding Transaction State Management in SQLite The core challenge in this scenario revolves around programmatically determining whether a transaction is active within an SQLite database connection when specific API functions return non-OK status codes. This is critical for deciding whether to issue ROLLBACK commands while processing user-provided SQL that may or may not contain explicit…
Understanding SQLite Resource Management and fork() Behavior in Unix Issue Overview: Risks of Inheriting SQLite Connections and Resources After fork() The core challenge when using SQLite in Unix environments that involve fork() system calls revolves around resource inheritance and synchronization. SQLite is designed for safe concurrent access under specific conditions, but the Unix fork() primitive…