22 add join (#143)

njord/src/condition.rs

@@ -74,7 +74,10 @@ impl Condition {
     pub fn build(&self) -> String {
         match self {
             Condition::Eq(column, value) => {
-                if Condition::is_numeric(value) {
+                // If contains a dot, assume it's a table.column
+                if column.contains('.') {
+                    format!("{} = {}", column, value)
+                } else if Condition::is_numeric(value) {
                     format!("{} = {}", column, value)
                 } else {
                     format!("{} = '{}'", column, value)

njord/src/sqlite/select.rs

@@ -35,14 +35,14 @@ use crate::{
         generate_order_by_str, generate_where_condition_str,
     },
 };
-use std::collections::HashMap;
-
 use rusqlite::{Connection, Result};
+use std::{collections::HashMap, sync::Arc};
 
 use log::info;
 use rusqlite::types::Value;
 
 use crate::table::Table;
+use crate::util::{Join, JoinType};
 
 /// Constructs a new SELECT query builder.
 ///
@@ -76,6 +76,7 @@ pub struct SelectQueryBuilder<'a, T: Table + Default> {
     having_condition: Option<Condition>,
     except_clauses: Option<Vec<SelectQueryBuilder<'a, T>>>,
     union_clauses: Option<Vec<SelectQueryBuilder<'a, T>>>,
+    joins: Option<Vec<Join>>,
 }
 
 impl<'a, T: Table + Default> SelectQueryBuilder<'a, T> {
@@ -99,6 +100,7 @@ impl<'a, T: Table + Default> SelectQueryBuilder<'a, T> {
             having_condition: None,
             except_clauses: None,
             union_clauses: None,
+            joins: None,
         }
     }
 
@@ -234,6 +236,35 @@ impl<'a, T: Table + Default> SelectQueryBuilder<'a, T> {
         self
     }
 
+    /// Adds a JOIN clause to the query, allowing you to combine rows from two or more tables based on a related column.
+    ///
+    /// This method modifies the current query builder to include a join clause with the specified join type,
+    /// target table, and condition for the join. If there are already existing JOIN clauses, the new clause
+    /// will be added to the list. If no JOIN clauses exist, a new list will be created with the provided
+    /// join information.
+    ///
+    /// # Arguments
+    ///
+    /// * `join_type` - The type of join to perform (e.g., INNER, LEFT, RIGHT, FULL).
+    /// * `table` - The table to join with the current table.
+    /// * `on_condition` - The condition that specifies how the tables are related (the ON clause).
+    ///
+    /// # Returns
+    ///
+    /// Returns the modified `SelectQueryBuilder` instance with the new JOIN clause added.
+    pub fn join(
+        mut self,
+        join_type: JoinType,
+        table: Arc<dyn Table>,
+        on_condition: Condition,
+    ) -> Self {
+        match self.joins {
+            Some(ref mut joins) => joins.push(Join::new(join_type, table, on_condition)),
+            None => self.joins = Some(vec![Join::new(join_type, table, on_condition)]),
+        }
+        self
+    }
+
     /// Builds the query string, this function should be used internally.
     pub fn build_query(&self) -> String {
         let columns_str = self
@@ -249,6 +280,29 @@ impl<'a, T: Table + Default> SelectQueryBuilder<'a, T> {
             .map(|t| t.get_name().to_string())
             .unwrap_or("".to_string());
 
+        // Generate JOIN clauses, if any
+        let join_clauses: Vec<String> = match &self.joins {
+            Some(joins) => joins
+                .iter()
+                .map(|join| {
+                    let join_type_str = match join.join_type {
+                        JoinType::Inner => "INNER JOIN",
+                        JoinType::Left => "LEFT JOIN",
+                        JoinType::Right => "RIGHT JOIN",
+                        JoinType::Full => "FULL OUTER JOIN",
+                    };
+                    format!(
+                        "{} {} ON {}",
+                        join_type_str,
+                        join.table.get_name(),
+                        generate_where_condition_str(Some(join.on_condition.clone()))
+                            .replace("WHERE", "")
+                    )
+                })
+                .collect(),
+            None => Vec::new(),
+        };
+
         let distinct_str = if self.distinct { "DISTINCT " } else { "" };
         let where_condition_str = generate_where_condition_str(self.where_condition.clone());
         let group_by_str = generate_group_by_str(&self.group_by);
@@ -258,11 +312,19 @@ impl<'a, T: Table + Default> SelectQueryBuilder<'a, T> {
         let having_str =
             generate_having_str(self.group_by.is_some(), self.having_condition.as_ref());
 
+        // Create the JOIN clause or an empty string
+        let join_clause = if !join_clauses.is_empty() {
+            join_clauses.join(" ")
+        } else {
+            String::new()
+        };
+
         let mut query = format!(
-            "SELECT {}{} FROM {} {} {} {} {} {}",
+            "SELECT {}{} FROM {} {} {} {} {} {} {}",
             distinct_str,
             columns_str,
             table_name,
+            join_clause,
             where_condition_str,
             group_by_str,
             having_str,

njord/src/util.rs

@@ -27,6 +27,36 @@
 //! OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 //! OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+use std::sync::Arc;
+
+use crate::condition::Condition;
+use crate::table::Table;
+
+#[derive(Clone)]
+pub enum JoinType {
+    Inner,
+    Left,
+    Right,
+    Full,
+}
+
+#[derive(Clone)]
+pub struct Join {
+    pub join_type: JoinType,
+    pub table: Arc<dyn Table>,
+    pub on_condition: Condition,
+}
+
+impl Join {
+    pub fn new(join_type: JoinType, table: Arc<dyn Table>, on_condition: Condition) -> Self {
+        Join {
+            join_type,
+            table,
+            on_condition,
+        }
+    }
+}
+
 /// Converts values for SQL INSERT
 ///
 /// # Arguments

njord/tests/sqlite/delete_test.rs

@@ -1,8 +1,8 @@
+use super::User;
 use njord::condition::Condition;
 use njord::sqlite;
 use std::collections::HashMap;
 use std::path::Path;
-use super::User;
 
 #[test]
 fn delete() {
@@ -31,4 +31,4 @@ fn delete() {
             panic!("Failed to DELETE: {:?}", e);
         }
     }
-}
+}

njord/tests/sqlite/insert_test.rs

@@ -1,7 +1,7 @@
+use super::User;
 use njord::keys::AutoIncrementPrimaryKey;
 use njord::sqlite;
 use std::path::Path;
-use super::User;
 
 #[test]
 fn insert_row() {
@@ -25,4 +25,4 @@ fn insert_row() {
             panic!("Failed to INSERT: {:?}", e);
         }
     }
-}
+}

njord/tests/sqlite/mod.rs

@@ -1,8 +1,9 @@
-mod open_test;
-mod insert_test;
-mod update_test;
 mod delete_test;
+mod insert_test;
+mod open_test;
+mod select_joins_test;
 mod select_test;
+mod update_test;
 
 use njord::keys::{AutoIncrementPrimaryKey, PrimaryKey};
 use njord::table::Table;
@@ -44,4 +45,12 @@ pub struct Product {
     pub stock_quantity: usize,
     pub category: Category, // one-to-one relationship
     pub discount: f64,
-}
+}
+
+#[derive(Table)]
+#[table_name = "users"]
+pub struct UsersWithJoin {
+    username: String,
+    price: f64,
+    name: String,
+}

njord/tests/sqlite/open_test.rs

@@ -8,4 +8,4 @@ fn open_db() {
 
     let result = sqlite::open(db_path);
     assert!(result.is_ok());
-}
+}

njord/tests/sqlite/select_joins_test.rs

@@ -0,0 +1,81 @@
+use njord::column::Column;
+use njord::condition::Condition;
+use njord::sqlite;
+use njord::util::JoinType;
+use std::path::Path;
+use std::sync::Arc;
+
+use crate::{Product, UsersWithJoin};
+
+#[test]
+fn select_inner_join() {
+    let db_relative_path = "./db/select_join.db";
+    let db_path = Path::new(&db_relative_path);
+    let conn = sqlite::open(db_path);
+
+    // Assume we have pre-inserted some data into the users and products tables
+    let columns = vec![
+        Column::Text("users.username".to_string()),
+        Column::Text("products.name".to_string()),
+        Column::Text("products.price".to_string()),
+    ];
+
+    // Assuming a hypothetical join condition: users.id = products.user_id
+    let join_condition = Condition::Eq("users.id".to_string(), "products.user_id".to_string());
+    match conn {
+        Ok(c) => {
+            let result = sqlite::select(&c, columns)
+                .from(UsersWithJoin::default())
+                .join(
+                    JoinType::Inner,
+                    Arc::new(Product::default()),
+                    join_condition,
+                )
+                .build();
+            match result {
+                Ok(r) => {
+                    // Check the number of results and assert against expected values
+                    assert!(!r.is_empty(), "Expected results, but got none.");
+                    // Further assertions on expected data can be made here based on inserted data
+                }
+                Err(e) => panic!("Failed to SELECT with JOIN: {:?}", e),
+            };
+        }
+        Err(e) => panic!("Failed to SELECT: {:?}", e),
+    }
+}
+
+#[test]
+fn select_left_join() {
+    let db_relative_path = "./db/select_join.db";
+    let db_path = Path::new(&db_relative_path);
+    let conn = sqlite::open(db_path);
+
+    // Assume we have pre-inserted some data into the users and products tables
+    let columns = vec![
+        Column::Text("users.username".to_string()),
+        Column::Text("products.name".to_string()),
+        Column::Text("products.price".to_string()),
+    ];
+
+    // Assuming a hypothetical join condition: users.id = products.user_id
+    let join_condition = Condition::Eq("users.id".to_string(), "products.user_id".to_string());
+    match conn {
+        Ok(c) => {
+            let result = sqlite::select(&c, columns)
+                .from(UsersWithJoin::default())
+                .join(JoinType::Left, Arc::new(Product::default()), join_condition)
+                .build();
+            match result {
+                Ok(r) => {
+                    // Check the number of results and assert against expected values
+                    assert!(!r.is_empty(), "Expected results, but got none.");
+                    assert_eq!(r.len(), 2, "Expected 2 results from the LEFT JOIN query.");
+                    // Further assertions on expected data can be made here based on inserted data
+                }
+                Err(e) => panic!("Failed to SELECT with JOIN: {:?}", e),
+            };
+        }
+        Err(e) => panic!("Failed to SELECT: {:?}", e),
+    }
+}