abstract class Memo::Dialect::Base

• Memo::Dialect::Base
• Reference
• Object

Overview

Abstract interface for SQL dialect differences between SQLite and PostgreSQL.

Most SQL in Memo is cross-database compatible. This module only abstracts the patterns that differ:

• Insert-and-return-ID (last_insert_rowid vs RETURNING)
• Conflict handling (INSERT OR IGNORE, INSERT OR REPLACE)
• Implicit rowid (SQLite) vs explicit column (PostgreSQL)
• FTS5 (SQLite) vs tsvector/GIN (PostgreSQL)
• Schema DDL (AUTOINCREMENT, BLOB, REAL types)
• DB path discovery (pragma vs connection string)

Direct Known Subclasses

• Memo::Dialect::Postgres
• Memo::Dialect::SQLite

Defined in:

memo/dialect/base.cr

Instance Method Summary

• #database_name(db : DB::Database) : String | Nil

  The database's name on its server, for naming index files.

• #db_file_path(db : DB::Database) : String | Nil

  Get the database file path from a connection, if applicable.

• #drop_legacy_texts(db : DBHandle) : Nil

  Drop the tables content-addressed storage replaced (memo_texts and its full-text index).

• #embedding_rowid_column : String

  The column name for embedding row identity used as USearch key.

• #fts_join_sql : String

  Build FTS JOIN clause for search queries (joining a chunk's text).

• #fts_where_sql : String

  Build FTS WHERE clause for match queries.

• #insert_or_ignore_sql(table : String, columns : String, placeholders : String) : String

  Build INSERT OR IGNORE SQL.

• #insert_returning_id(db : DBHandle, sql : String, *args) : Int64

  Execute an INSERT and return the generated ID.

• #lock_for_migration(db : DB::Connection) : Nil

  Inside a migration's transaction: keep other processes from migrating the same database at the same time.

• #prepare(db : DB::Database) : Nil

  Bring existing tables up to date before the schema runs, where its statements depend on columns older databases lack.

• #schema_statements : Array(String)

  Get schema DDL statements.

• #table_exists?(db : DBHandle, table : String) : Bool
• #upsert_sql(table : String, columns : String, placeholders : String, conflict_columns : String, update_columns : Array(String)) : String

  Build upsert SQL (INSERT OR REPLACE equivalent).

Instance Method Detail