support partial index (#478)

* support partial index

* add tests for partial index

* update examples for partial index

* import once in src/index/create.rs

* fix an output in examples/postgres/Readme.md

* cargo fmt for  examples

* use bigdecimal:0.4.5

---------

Co-authored-by: Chris Tsang <[email protected]>

Author: kyoto7250

examples/diesel_postgres/Readme.md

@@ -1,7 +1,7 @@
 # SeaQuery Diesel Postgres example
 
 > WARN: If you enable `with-bigdecimal`, you HAVE to update the version used by default by `diesel`
-> otherwise it will fail to build. Use `cargo update -p bigdecimal:0.4.2 --precise 0.3.1`.
+> otherwise it will fail to build. Use `cargo update -p bigdecimal:0.4.5 --precise 0.3.1`.
 
 Running:
 

examples/diesel_sqlite/src/main.rs

@@ -5,7 +5,10 @@ use diesel::deserialize::{self, FromSql};
 use diesel::sql_types::BigInt;
 use diesel::sql_types::{Blob, Text};
 use diesel::{Connection, QueryableByName, RunQueryDsl, SqliteConnection};
-use sea_query::{Alias, ColumnDef, Expr, Func, Iden, Order, Query, SqliteQueryBuilder, Table};
+use sea_query::{
+    Alias, ColumnDef, ConditionalStatement, Expr, Func, Iden, Index, Order, Query,
+    SqliteQueryBuilder, Table,
+};
 use sea_query_diesel::DieselBinder;
 use serde_json::json;
 use time::macros::{date, time};
@@ -40,6 +43,13 @@ fn main() {
             .col(ColumnDef::new(Character::Meta).json().not_null())
             .col(ColumnDef::new(Character::Created).date_time())
             .build(SqliteQueryBuilder),
+        Index::create()
+            .name("partial_index_small_font")
+            .if_not_exists()
+            .table(Character::Table)
+            .col(Character::FontSize)
+            .and_where(Expr::col(Character::FontSize).lt(11).not())
+            .build(SqliteQueryBuilder),
     ]
     .join("; ");
 

examples/postgres/Readme.md

@@ -7,8 +7,8 @@ cargo run
 
 Example output:
 ```
-DROP TABLE IF EXISTS "document"; CREATE TABLE IF NOT EXISTS "document" ( "id" serial NOT NULL PRIMARY KEY, "json_field" jsonb, "timestamp" timestamp )
-Create table document: ()
+DROP TABLE IF EXISTS "document"; CREATE TABLE IF NOT EXISTS "document" ( "id" serial NOT NULL PRIMARY KEY, "uuid" uuid, "json_field" jsonb, "timestamp" timestamp, "timestamp_with_time_zone" timestamp with time zone, "decimal" decimal, "array" integer[] ); CREATE INDEX "partial_index_small_decimal" ON "document" ("decimal") WHERE NOT "decimal" < 11
+Create table document: Ok(())
 
 Insert into document: Ok(1)
 

examples/postgres/src/main.rs

@@ -2,7 +2,10 @@ use chrono::{DateTime, FixedOffset, NaiveDate, NaiveDateTime};
 
 use postgres::{Client, NoTls, Row};
 use rust_decimal::Decimal;
-use sea_query::{ColumnDef, ColumnType, Iden, Order, PostgresQueryBuilder, Query, Table};
+use sea_query::{
+    ColumnDef, ColumnType, ConditionalStatement, Expr, Iden, Index, Order, PostgresQueryBuilder,
+    Query, Table,
+};
 use sea_query_postgres::PostgresBinder;
 use time::{
     macros::{date, offset, time},
@@ -37,6 +40,12 @@ fn main() {
             .col(ColumnDef::new(Document::Decimal).decimal())
             .col(ColumnDef::new(Document::Array).array(ColumnType::Integer))
             .build(PostgresQueryBuilder),
+        Index::create()
+            .name("partial_index_small_decimal")
+            .table(Document::Table)
+            .col(Document::Decimal)
+            .and_where(Expr::col(Document::Decimal).lt(11).not())
+            .build(PostgresQueryBuilder),
     ]
     .join("; ");
 

examples/rusqlite/src/main.rs

@@ -1,7 +1,9 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use rusqlite::{Connection, Result, Row};
-use sea_query::{ColumnDef, Expr, Func, Iden, Order, Query, SqliteQueryBuilder, Table};
-
+use sea_query::{
+    ColumnDef, ConditionalStatement, Expr, Func, Iden, Index, Order, Query, SqliteQueryBuilder,
+    Table,
+};
 use sea_query_rusqlite::RusqliteBinder;
 use serde_json::{json, Value as Json};
 use time::{
@@ -37,6 +39,12 @@ fn main() -> Result<()> {
             .col(ColumnDef::new(Character::Meta).json())
             .col(ColumnDef::new(Character::Created).date_time())
             .build(SqliteQueryBuilder),
+        Index::create()
+            .name("partial_index_small_font")
+            .table(Character::Table)
+            .col(Character::FontSize)
+            .and_where(Expr::col(Character::FontSize).lt(11).not())
+            .build(SqliteQueryBuilder),
     ]
     .join("; ");
 

examples/sqlx_postgres/Readme.md

@@ -9,6 +9,8 @@ Example output:
 ```
 Create table character: Ok(PgQueryResult { rows_affected: 0 })
 
+Create partial index: Ok(PgQueryResult { rows_affected: 0 })
+
 Insert into character: Ok(PgQueryResult { rows_affected: 1 })
 
 Select one from character:

examples/sqlx_postgres/src/main.rs

@@ -2,7 +2,8 @@ use bigdecimal::{BigDecimal, FromPrimitive};
 use chrono::{NaiveDate, NaiveDateTime};
 use rust_decimal::Decimal;
 use sea_query::{
-    ColumnDef, Expr, Func, Iden, OnConflict, Order, PostgresQueryBuilder, Query, Table,
+    ColumnDef, ConditionalStatement, Expr, Func, Iden, Index, OnConflict, Order,
+    PostgresQueryBuilder, Query, Table,
 };
 use sea_query_binder::SqlxBinder;
 use sqlx::{PgPool, Row};
@@ -50,6 +51,18 @@ async fn main() {
     let result = sqlx::query(&sql).execute(&mut *pool).await;
     println!("Create table character: {result:?}\n");
 
+    // Partial Index
+    let partial_index = Index::create()
+        .if_not_exists()
+        .name("partial_index_small_font")
+        .table(Character::Table)
+        .col(Character::FontSize)
+        .and_where(Expr::col(Character::FontSize).lt(11).not())
+        .build(PostgresQueryBuilder);
+
+    let index = sqlx::query(&partial_index).execute(&mut *pool).await;
+    println!("Create partial index: {index:?}\n");
+
     // Create
 
     let (sql, values) = Query::insert()

examples/sqlx_sqlite/Readme.md

@@ -9,6 +9,8 @@ Example output:
 ```
 Create table character: Ok(SqliteQueryResult { changes: 0, last_insert_rowid: 0 })
 
+Create partial index: Ok(SqliteQueryResult { changes: 0, last_insert_rowid: 0 })
+
 Insert into character: last_insert_id = 1
 
 Select one from character:

examples/sqlx_sqlite/src/main.rs

@@ -1,5 +1,8 @@
 use chrono::{NaiveDate, NaiveDateTime};
-use sea_query::{ColumnDef, Expr, Func, Iden, OnConflict, Order, Query, SqliteQueryBuilder, Table};
+use sea_query::{
+    ColumnDef, ConditionalStatement, Expr, Func, Iden, Index, OnConflict, Order, Query,
+    SqliteQueryBuilder, Table,
+};
 use sea_query_binder::SqlxBinder;
 use serde_json::{json, Value as Json};
 use sqlx::{Row, SqlitePool};
@@ -34,6 +37,17 @@ async fn main() {
     let result = sqlx::query(&sql).execute(&pool).await;
     println!("Create table character: {result:?}\n");
 
+    // Partial Index
+    let partial_index = Index::create()
+        .name("partial_index_small_font")
+        .table(Character::Table)
+        .col(Character::FontSize)
+        .and_where(Expr::col(Character::FontSize).lt(11).not())
+        .build(SqliteQueryBuilder);
+
+    let index = sqlx::query(&partial_index).execute(&pool).await;
+    println!("Create partial index: {index:?}\n");
+
     // Create
     let (sql, values) = Query::insert()
         .into_table(Character::Table)

src/backend/index_builder.rs

@@ -23,6 +23,8 @@ pub trait IndexBuilder: QuotedBuilder + TableRefBuilder {
         self.prepare_index_prefix(create, sql);
 
         self.prepare_index_columns(&create.index.columns, sql);
+
+        self.prepare_filter(&create.r#where, sql);
     }
 
     /// Translate [`IndexCreateStatement`] into SQL statement.
@@ -74,4 +76,8 @@ pub trait IndexBuilder: QuotedBuilder + TableRefBuilder {
         });
         write!(sql, ")").unwrap();
     }
+
+    #[doc(hidden)]
+    // Write WHERE clause for partial index. This function is not available in MySQL.
+    fn prepare_filter(&self, _condition: &ConditionHolder, _sql: &mut dyn SqlWriter) {}
 }