fix: Add is_nullable field support to MySQL metadata provider

Author: shefeek-jinnah

src/metadata_provider_mysql.rs

@@ -139,7 +139,7 @@ impl MetadataProvider for MySqlMetadataProvider {
     fn get_table_structure(&self, table_id: i64) -> Result<Vec<DuckLakeTableColumn>> {
         block_on(async {
             let rows = sqlx::query(
-                "SELECT column_id, column_name, column_type
+                "SELECT column_id, column_name, column_type, nulls_allowed
                  FROM ducklake_column
                  WHERE table_id = ?
                  ORDER BY column_order",
@@ -150,10 +150,12 @@ impl MetadataProvider for MySqlMetadataProvider {
 
             rows.into_iter()
                 .map(|row| {
+                    let nulls_allowed: Option<bool> = row.try_get(3)?;
                     Ok(DuckLakeTableColumn {
                         column_id: row.try_get(0)?,
                         column_name: row.try_get(1)?,
                         column_type: row.try_get(2)?,
+                        is_nullable: nulls_allowed.unwrap_or(true),
                     })
                 })
                 .collect()
@@ -356,7 +358,7 @@ impl MetadataProvider for MySqlMetadataProvider {
     fn list_all_columns(&self, snapshot_id: i64) -> Result<Vec<ColumnWithTable>> {
         block_on(async {
             let rows = sqlx::query(
-                "SELECT s.schema_name, t.table_name, c.column_id, c.column_name, c.column_type
+                "SELECT s.schema_name, t.table_name, c.column_id, c.column_name, c.column_type, c.nulls_allowed
                  FROM ducklake_schema s
                  JOIN ducklake_table t ON s.schema_id = t.schema_id
                  JOIN ducklake_column c ON t.table_id = c.table_id
@@ -377,10 +379,12 @@ impl MetadataProvider for MySqlMetadataProvider {
                 .map(|row| {
                     let schema_name: String = row.try_get(0)?;
                     let table_name: String = row.try_get(1)?;
+                    let nulls_allowed: Option<bool> = row.try_get(5)?;
                     let column = DuckLakeTableColumn {
                         column_id: row.try_get(2)?,
                         column_name: row.try_get(3)?,
                         column_type: row.try_get(4)?,
+                        is_nullable: nulls_allowed.unwrap_or(true),
                     };
                     Ok(ColumnWithTable {
                         schema_name,

tests/mysql_metadata_provider_test.rs

@@ -77,6 +77,7 @@ async fn init_schema(pool: &MySqlPool) -> anyhow::Result<()> {
             column_name VARCHAR(255) NOT NULL,
             column_type VARCHAR(255) NOT NULL,
             column_order INTEGER NOT NULL,
+            nulls_allowed BOOLEAN,
             FOREIGN KEY (table_id) REFERENCES ducklake_table(table_id)
         )",
     )
@@ -254,38 +255,41 @@ async fn populate_test_data(provider: &MySqlMetadataProvider) -> anyhow::Result<
 
     // Insert columns for users table
     sqlx::query(
-        "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order)
-         VALUES (?, ?, ?, ?, ?)",
+        "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order, nulls_allowed)
+         VALUES (?, ?, ?, ?, ?, ?)",
     )
     .bind(1i64)
     .bind(1i64)
     .bind("id")
     .bind("INT")
     .bind(0i32)
+    .bind(false)
     .execute(pool)
     .await?;
 
     sqlx::query(
-        "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order)
-         VALUES (?, ?, ?, ?, ?)",
+        "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order, nulls_allowed)
+         VALUES (?, ?, ?, ?, ?, ?)",
     )
     .bind(2i64)
     .bind(1i64)
     .bind("name")
     .bind("VARCHAR")
     .bind(1i32)
+    .bind(true)
     .execute(pool)
     .await?;
 
     sqlx::query(
-        "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order)
-         VALUES (?, ?, ?, ?, ?)",
+        "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order, nulls_allowed)
+         VALUES (?, ?, ?, ?, ?, ?)",
     )
     .bind(3i64)
     .bind(1i64)
     .bind("email")
     .bind("VARCHAR")
     .bind(2i32)
+    .bind(true)
     .execute(pool)
     .await?;
 
@@ -422,14 +426,15 @@ async fn populate_from_duckdb_catalog(
 
             for (order, column) in columns.iter().enumerate() {
                 sqlx::query(
-                    "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order)
-                     VALUES (?, ?, ?, ?, ?)"
+                    "INSERT INTO ducklake_column (column_id, table_id, column_name, column_type, column_order, nulls_allowed)
+                     VALUES (?, ?, ?, ?, ?, ?)"
                 )
                 .bind(column.column_id)
                 .bind(table.table_id)
                 .bind(&column.column_name)
                 .bind(&column.column_type)
                 .bind(order as i32)
+                .bind(column.is_nullable)
                 .execute(pool)
                 .await?;
             }