巴利全文搜索表

db/postgresql/migrations/2021-12-03-150805_fts_texts/down.sql

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+-- This file should undo anything in `up.sql`
+
+DROP TABLE fts_texts ;
+
+DROP TEXT SEARCH CONFIGURATION pali;
+
+DROP TEXT SEARCH CONFIGURATION pali_unaccent;
+
+DROP TEXT SEARCH DICTIONARY pali_stem;
+
+DROP TEXT SEARCH DICTIONARY pali_stopwords;
+
+DROP FUNCTION query_pali;

db/postgresql/migrations/2021-12-03-150805_fts_texts/up.sql

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+-- Your SQL goes here
+
+-- 创建表结构
+
+CREATE TABLE fts_texts (
+       paragraph        integer,
+       book             integer,
+       wid              varchar(50),
+       -- 单个出现的黑体字，权重较大
+       bold_single      text,
+       -- 成对出现的黑体字，权重一般
+       bold_double      text,
+       -- 连续三个或三个以上的黑体字，权重较低
+       bold_multiple    text,
+       content          text
+);
+
+-- 创建全文检索配置 pali
+CREATE TEXT SEARCH CONFIGURATION pali ( parser = pg_catalog.default );
+
+-- 创建全文检索配置 pali_unaccent 无标音符号版
+CREATE TEXT SEARCH CONFIGURATION pali_unaccent ( parser = pg_catalog.default );
+
+-- 创建巴利语词形转换字典
+CREATE TEXT SEARCH DICTIONARY pali_stem (
+    TEMPLATE = synonym,
+    SYNONYMS = pali
+);
+
+-- 创建巴利语停用词字典
+CREATE TEXT SEARCH DICTIONARY pali_stopwords (
+    TEMPLATE = pg_catalog.simple, STOPWORDS = pali,
+    ACCEPT = true
+);
+
+-- 修改全文检索配置 pali 使用我们创建的字典
+ALTER TEXT SEARCH CONFIGURATION pali
+    ADD MAPPING FOR asciiword, word, hword_part, hword_asciipart
+    WITH pali_stem, pali_stopwords;
+
+-- 修改全文检索配置 pali_unaccent 使用我们创建的字典
+
+CREATE EXTENSION IF NOT EXISTS "unaccent";
+
+ALTER TEXT SEARCH CONFIGURATION pali_unaccent
+    ADD MAPPING FOR asciiword, word, hword_part, hword_asciipart
+    WITH unaccent, pali_stem, pali_stopwords;
+
+
+-- 添加自动更新的 TSVECTOR 字段
+
+ALTER TABLE fts_texts
+      ADD COLUMN full_text_search_weighted TSVECTOR
+      GENERATED ALWAYS AS (
+         setweight(to_tsvector('pali', coalesce(content,'')), 'A')  || ' ' ||
+         setweight(to_tsvector('pali', coalesce(bold_single,'')), 'B') || ' '  ||
+         setweight(to_tsvector('pali', coalesce(bold_double,'')), 'C') || ' ' ||
+         setweight(to_tsvector('pali', coalesce(bold_multiple,'')), 'D')
+      ) STORED;
+
+ALTER TABLE fts_texts
+      ADD COLUMN full_text_search_weighted_unaccent TSVECTOR
+      GENERATED ALWAYS AS (
+         setweight(to_tsvector('pali_unaccent', coalesce(content,'')), 'A')  || ' ' ||
+         setweight(to_tsvector('pali_unaccent', coalesce(bold_single,'')), 'B') || ' '  ||
+         setweight(to_tsvector('pali_unaccent', coalesce(bold_double,'')), 'C') || ' ' ||
+         setweight(to_tsvector('pali_unaccent', coalesce(bold_multiple,'')), 'D')
+      ) STORED;
+
+-- 为该字段创建索引
+
+CREATE INDEX full_text_search_weighted_idx
+       ON fts_texts USING GIN (full_text_search_weighted);
+
+CREATE INDEX full_text_search_weighted__unaccent_idx
+       ON fts_texts USING GIN (full_text_search_weighted_unaccent);
+
+-- 创建查询函数
+
+CREATE OR REPLACE FUNCTION query_pali(query_str TEXT) 
+  RETURNS TABLE(
+          rank NUMERIC,
+          paragraph INTEGER,
+          wid VARCHAR,
+          bold_single TEXT,
+          bold_double TEXT,
+          bold_multiple TEXT,
+          content TEXT,
+          full_text_search_weighted TSVECTOR,
+          full_text_search_weighted_unaccent TSVECTOR) 
+AS $$
+    SELECT
+    ts_rank('{0.1, 0.2, 0.4, 1}',
+        full_text_search_weighted,
+        websearch_to_tsquery('pali', query_str)) +
+    ts_rank('{0.1, 0.2, 0.4, 1}',
+        full_text_search_weighted_unaccent,
+        websearch_to_tsquery('pali_unaccent', query_str)), -- AS rank
+        paragraph, wid, bold_single, bold_double, bold_multiple, content,
+        full_text_search_weighted, full_text_search_weighted_unaccent
+    FROM fts_texts
+    WHERE
+        full_text_search_weighted @@ websearch_to_tsquery('pali', query_str) OR
+        full_text_search_weighted_unaccent @@ websearch_to_tsquery('pali_unaccent', query_str);
+$$ LANGUAGE SQL;