feat: add ER diagram and enhance TableStructure with FK details, triggers, comments

- Add interactive ER diagram with ReactFlow + dagre auto-layout, accessible
  via right-click context menu on schema nodes in the sidebar
- Enhance TableStructure: column comments, FK referenced table/columns,
  ON UPDATE/DELETE rules, new Triggers tab
- Backend: rewrite get_table_constraints using pg_constraint for proper
  composite FK support, add get_table_triggers and get_schema_erd commands

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src-tauri/src/commands/schema.rs

@@ -1,5 +1,8 @@
 use crate::error::{TuskError, TuskResult};
-use crate::models::schema::{ColumnDetail, ColumnInfo, ConstraintInfo, IndexInfo, SchemaObject};
+use crate::models::schema::{
+    ColumnDetail, ColumnInfo, ConstraintInfo, ErdColumn, ErdData, ErdRelationship, ErdTable,
+    IndexInfo, SchemaObject, TriggerInfo,
+};
 use crate::state::{AppState, DbFlavor};
 use sqlx::Row;
 use std::collections::HashMap;
@@ -271,7 +274,13 @@ pub async fn get_table_columns_core(
                     AND tc.table_name = $2 \
                     AND kcu.column_name = c.column_name \
                 LIMIT 1 \
-            ), false) as is_pk \
+            ), false) as is_pk, \
+            col_description( \
+                (SELECT oid FROM pg_class \
+                 JOIN pg_namespace ON pg_namespace.oid = pg_class.relnamespace \
+                 WHERE relname = $2 AND nspname = $1), \
+                c.ordinal_position \
+            ) as col_comment \
          FROM information_schema.columns c \
          WHERE c.table_schema = $1 AND c.table_name = $2 \
          ORDER BY c.ordinal_position",
@@ -292,6 +301,7 @@ pub async fn get_table_columns_core(
             ordinal_position: r.get::<i32, _>(4),
             character_maximum_length: r.get::<Option<i32>, _>(5),
             is_primary_key: r.get::<bool, _>(6),
+            comment: r.get::<Option<String>, _>(7),
         })
         .collect())
 }
@@ -320,16 +330,49 @@ pub async fn get_table_constraints(
 
     let rows = sqlx::query(
         "SELECT \
-            tc.constraint_name, \
-            tc.constraint_type, \
-            array_agg(kcu.column_name ORDER BY kcu.ordinal_position)::text[] as columns \
-         FROM information_schema.table_constraints tc \
-         JOIN information_schema.key_column_usage kcu \
-            ON tc.constraint_name = kcu.constraint_name \
-            AND tc.table_schema = kcu.table_schema \
-         WHERE tc.table_schema = $1 AND tc.table_name = $2 \
-         GROUP BY tc.constraint_name, tc.constraint_type \
-         ORDER BY tc.constraint_type, tc.constraint_name",
+            c.conname AS constraint_name, \
+            CASE c.contype \
+                WHEN 'p' THEN 'PRIMARY KEY' \
+                WHEN 'f' THEN 'FOREIGN KEY' \
+                WHEN 'u' THEN 'UNIQUE' \
+                WHEN 'c' THEN 'CHECK' \
+                WHEN 'x' THEN 'EXCLUDE' \
+            END AS constraint_type, \
+            ARRAY( \
+                SELECT a.attname FROM unnest(c.conkey) WITH ORDINALITY AS k(attnum, ord) \
+                JOIN pg_attribute a ON a.attrelid = c.conrelid AND a.attnum = k.attnum \
+                ORDER BY k.ord \
+            )::text[] AS columns, \
+            ref_ns.nspname AS referenced_schema, \
+            ref_cl.relname AS referenced_table, \
+            CASE WHEN c.confrelid > 0 THEN ARRAY( \
+                SELECT a.attname FROM unnest(c.confkey) WITH ORDINALITY AS k(attnum, ord) \
+                JOIN pg_attribute a ON a.attrelid = c.confrelid AND a.attnum = k.attnum \
+                ORDER BY k.ord \
+            )::text[] ELSE NULL END AS referenced_columns, \
+            CASE c.confupdtype \
+                WHEN 'a' THEN 'NO ACTION' \
+                WHEN 'r' THEN 'RESTRICT' \
+                WHEN 'c' THEN 'CASCADE' \
+                WHEN 'n' THEN 'SET NULL' \
+                WHEN 'd' THEN 'SET DEFAULT' \
+                ELSE NULL \
+            END AS update_rule, \
+            CASE c.confdeltype \
+                WHEN 'a' THEN 'NO ACTION' \
+                WHEN 'r' THEN 'RESTRICT' \
+                WHEN 'c' THEN 'CASCADE' \
+                WHEN 'n' THEN 'SET NULL' \
+                WHEN 'd' THEN 'SET DEFAULT' \
+                ELSE NULL \
+            END AS delete_rule \
+         FROM pg_constraint c \
+         JOIN pg_class cl ON cl.oid = c.conrelid \
+         JOIN pg_namespace ns ON ns.oid = cl.relnamespace \
+         LEFT JOIN pg_class ref_cl ON ref_cl.oid = c.confrelid \
+         LEFT JOIN pg_namespace ref_ns ON ref_ns.oid = ref_cl.relnamespace \
+         WHERE ns.nspname = $1 AND cl.relname = $2 \
+         ORDER BY c.contype, c.conname",
     )
     .bind(&schema)
     .bind(&table)
@@ -343,6 +386,11 @@ pub async fn get_table_constraints(
             name: r.get::<String, _>(0),
             constraint_type: r.get::<String, _>(1),
             columns: r.get::<Vec<String>, _>(2),
+            referenced_schema: r.get::<Option<String>, _>(3),
+            referenced_table: r.get::<Option<String>, _>(4),
+            referenced_columns: r.get::<Option<Vec<String>>, _>(5),
+            update_rule: r.get::<Option<String>, _>(6),
+            delete_rule: r.get::<Option<String>, _>(7),
         })
         .collect())
 }
@@ -483,3 +531,186 @@ pub async fn get_column_details(
         })
         .collect())
 }
+
+#[tauri::command]
+pub async fn get_table_triggers(
+    state: State<'_, Arc<AppState>>,
+    connection_id: String,
+    schema: String,
+    table: String,
+) -> TuskResult<Vec<TriggerInfo>> {
+    let pools = state.pools.read().await;
+    let pool = pools
+        .get(&connection_id)
+        .ok_or(TuskError::NotConnected(connection_id))?;
+
+    let rows = sqlx::query(
+        "SELECT \
+            t.tgname AS trigger_name, \
+            CASE \
+                WHEN t.tgtype::int & 2 = 2 THEN 'BEFORE' \
+                WHEN t.tgtype::int & 2 = 0 AND t.tgtype::int & 64 = 64 THEN 'INSTEAD OF' \
+                ELSE 'AFTER' \
+            END AS timing, \
+            array_to_string(ARRAY[ \
+                CASE WHEN t.tgtype::int & 4 = 4 THEN 'INSERT' ELSE NULL END, \
+                CASE WHEN t.tgtype::int & 8 = 8 THEN 'DELETE' ELSE NULL END, \
+                CASE WHEN t.tgtype::int & 16 = 16 THEN 'UPDATE' ELSE NULL END, \
+                CASE WHEN t.tgtype::int & 32 = 32 THEN 'TRUNCATE' ELSE NULL END \
+            ], ' OR ') AS event, \
+            CASE WHEN t.tgtype::int & 1 = 1 THEN 'ROW' ELSE 'STATEMENT' END AS orientation, \
+            p.proname AS function_name, \
+            t.tgenabled != 'D' AS is_enabled, \
+            pg_get_triggerdef(t.oid) AS definition \
+         FROM pg_trigger t \
+         JOIN pg_class c ON c.oid = t.tgrelid \
+         JOIN pg_namespace n ON n.oid = c.relnamespace \
+         JOIN pg_proc p ON p.oid = t.tgfoid \
+         WHERE n.nspname = $1 AND c.relname = $2 AND NOT t.tgisinternal \
+         ORDER BY t.tgname",
+    )
+    .bind(&schema)
+    .bind(&table)
+    .fetch_all(pool)
+    .await
+    .map_err(TuskError::Database)?;
+
+    Ok(rows
+        .iter()
+        .map(|r| TriggerInfo {
+            name: r.get::<String, _>(0),
+            timing: r.get::<String, _>(1),
+            event: r.get::<String, _>(2),
+            orientation: r.get::<String, _>(3),
+            function_name: r.get::<String, _>(4),
+            is_enabled: r.get::<bool, _>(5),
+            definition: r.get::<String, _>(6),
+        })
+        .collect())
+}
+
+#[tauri::command]
+pub async fn get_schema_erd(
+    state: State<'_, Arc<AppState>>,
+    connection_id: String,
+    schema: String,
+) -> TuskResult<ErdData> {
+    let pools = state.pools.read().await;
+    let pool = pools
+        .get(&connection_id)
+        .ok_or(TuskError::NotConnected(connection_id))?;
+
+    // Get all tables with columns
+    let col_rows = sqlx::query(
+        "SELECT \
+            c.table_name, \
+            c.column_name, \
+            c.data_type, \
+            c.is_nullable = 'YES' AS is_nullable, \
+            COALESCE(( \
+                SELECT true FROM pg_constraint con \
+                JOIN pg_class cl ON cl.oid = con.conrelid \
+                JOIN pg_namespace ns ON ns.oid = cl.relnamespace \
+                WHERE con.contype = 'p' \
+                    AND ns.nspname = $1 AND cl.relname = c.table_name \
+                    AND EXISTS ( \
+                        SELECT 1 FROM unnest(con.conkey) k \
+                        JOIN pg_attribute a ON a.attrelid = con.conrelid AND a.attnum = k \
+                        WHERE a.attname = c.column_name \
+                    ) \
+                LIMIT 1 \
+            ), false) AS is_pk \
+         FROM information_schema.columns c \
+         JOIN information_schema.tables t \
+            ON t.table_schema = c.table_schema AND t.table_name = c.table_name \
+         WHERE c.table_schema = $1 AND t.table_type = 'BASE TABLE' \
+         ORDER BY c.table_name, c.ordinal_position",
+    )
+    .bind(&schema)
+    .fetch_all(pool)
+    .await
+    .map_err(TuskError::Database)?;
+
+    // Build tables map
+    let mut tables_map: HashMap<String, ErdTable> = HashMap::new();
+    for row in &col_rows {
+        let table_name: String = row.get(0);
+        let entry = tables_map.entry(table_name.clone()).or_insert_with(|| ErdTable {
+            schema: schema.clone(),
+            name: table_name,
+            columns: Vec::new(),
+        });
+        entry.columns.push(ErdColumn {
+            name: row.get(1),
+            data_type: row.get(2),
+            is_nullable: row.get(3),
+            is_primary_key: row.get(4),
+        });
+    }
+    let tables: Vec<ErdTable> = tables_map.into_values().collect();
+
+    // Get all FK relationships
+    let fk_rows = sqlx::query(
+        "SELECT \
+            c.conname AS constraint_name, \
+            src_ns.nspname AS source_schema, \
+            src_cl.relname AS source_table, \
+            ARRAY( \
+                SELECT a.attname FROM unnest(c.conkey) WITH ORDINALITY AS k(attnum, ord) \
+                JOIN pg_attribute a ON a.attrelid = c.conrelid AND a.attnum = k.attnum \
+                ORDER BY k.ord \
+            )::text[] AS source_columns, \
+            ref_ns.nspname AS target_schema, \
+            ref_cl.relname AS target_table, \
+            ARRAY( \
+                SELECT a.attname FROM unnest(c.confkey) WITH ORDINALITY AS k(attnum, ord) \
+                JOIN pg_attribute a ON a.attrelid = c.confrelid AND a.attnum = k.attnum \
+                ORDER BY k.ord \
+            )::text[] AS target_columns, \
+            CASE c.confupdtype \
+                WHEN 'a' THEN 'NO ACTION' \
+                WHEN 'r' THEN 'RESTRICT' \
+                WHEN 'c' THEN 'CASCADE' \
+                WHEN 'n' THEN 'SET NULL' \
+                WHEN 'd' THEN 'SET DEFAULT' \
+            END AS update_rule, \
+            CASE c.confdeltype \
+                WHEN 'a' THEN 'NO ACTION' \
+                WHEN 'r' THEN 'RESTRICT' \
+                WHEN 'c' THEN 'CASCADE' \
+                WHEN 'n' THEN 'SET NULL' \
+                WHEN 'd' THEN 'SET DEFAULT' \
+            END AS delete_rule \
+         FROM pg_constraint c \
+         JOIN pg_class src_cl ON src_cl.oid = c.conrelid \
+         JOIN pg_namespace src_ns ON src_ns.oid = src_cl.relnamespace \
+         JOIN pg_class ref_cl ON ref_cl.oid = c.confrelid \
+         JOIN pg_namespace ref_ns ON ref_ns.oid = ref_cl.relnamespace \
+         WHERE c.contype = 'f' AND src_ns.nspname = $1 \
+         ORDER BY c.conname",
+    )
+    .bind(&schema)
+    .fetch_all(pool)
+    .await
+    .map_err(TuskError::Database)?;
+
+    let relationships: Vec<ErdRelationship> = fk_rows
+        .iter()
+        .map(|r| ErdRelationship {
+            constraint_name: r.get(0),
+            source_schema: r.get(1),
+            source_table: r.get(2),
+            source_columns: r.get(3),
+            target_schema: r.get(4),
+            target_table: r.get(5),
+            target_columns: r.get(6),
+            update_rule: r.get(7),
+            delete_rule: r.get(8),
+        })
+        .collect();
+
+    Ok(ErdData {
+        tables,
+        relationships,
+    })
+}

src-tauri/src/lib.rs

@@ -59,6 +59,8 @@ pub fn run() {
             commands::schema::get_table_indexes,
             commands::schema::get_completion_schema,
             commands::schema::get_column_details,
+            commands::schema::get_table_triggers,
+            commands::schema::get_schema_erd,
             // data
             commands::data::get_table_data,
             commands::data::update_row,

src-tauri/src/models/schema.rs

@@ -18,6 +18,7 @@ pub struct ColumnInfo {
     pub ordinal_position: i32,
     pub character_maximum_length: Option<i32>,
     pub is_primary_key: bool,
+    pub comment: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -34,6 +35,11 @@ pub struct ConstraintInfo {
     pub name: String,
     pub constraint_type: String,
     pub columns: Vec<String>,
+    pub referenced_schema: Option<String>,
+    pub referenced_table: Option<String>,
+    pub referenced_columns: Option<Vec<String>>,
+    pub update_rule: Option<String>,
+    pub delete_rule: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -43,3 +49,48 @@ pub struct IndexInfo {
     pub is_unique: bool,
     pub is_primary: bool,
 }
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct TriggerInfo {
+    pub name: String,
+    pub event: String,
+    pub timing: String,
+    pub orientation: String,
+    pub function_name: String,
+    pub is_enabled: bool,
+    pub definition: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ErdColumn {
+    pub name: String,
+    pub data_type: String,
+    pub is_nullable: bool,
+    pub is_primary_key: bool,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ErdTable {
+    pub schema: String,
+    pub name: String,
+    pub columns: Vec<ErdColumn>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ErdRelationship {
+    pub constraint_name: String,
+    pub source_schema: String,
+    pub source_table: String,
+    pub source_columns: Vec<String>,
+    pub target_schema: String,
+    pub target_table: String,
+    pub target_columns: Vec<String>,
+    pub update_rule: String,
+    pub delete_rule: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ErdData {
+    pub tables: Vec<ErdTable>,
+    pub relationships: Vec<ErdRelationship>,
+}