feat: add QuestDB support

Thanks @ptma!

crates/dbx-core/src/table_structure_sql/column_alter.rs

@@ -551,6 +551,29 @@ pub(super) fn build_sqlite_existing_column_sql(
     statements
 }
 
+pub(super) fn build_questdb_existing_column_sql(table: &str, column: &EditableStructureColumn) -> Vec<String> {
+    let Some(original) = &column.original else {
+        return Vec::new();
+    };
+    let mut statements = Vec::new();
+    let current_name = &column.name;
+    if column.name != original.name {
+        statements.push(format!(
+            "ALTER TABLE {table} RENAME COLUMN {} TO {};",
+            quote_ident(StructureDialect::Questdb, &original.name),
+            quote_ident(StructureDialect::Questdb, &column.name)
+        ));
+    }
+    if column.data_type.trim() != original.data_type.trim() {
+        statements.push(format!(
+            "ALTER TABLE {table} ALTER COLUMN {} TYPE {};",
+            quote_ident(StructureDialect::Questdb, current_name),
+            column_data_type(StructureDialect::Questdb, column)
+        ));
+    }
+    statements
+}
+
 pub(super) fn has_existing_column_attribute_change(column: &EditableStructureColumn) -> bool {
     let Some(original) = &column.original else {
         return false;

crates/dbx-core/src/table_structure_sql/column_format.rs

@@ -5,6 +5,11 @@ use super::util::{clean, format_default_for_sql, normalize_default, quote_ident,
 pub(super) fn column_definition(dialect: StructureDialect, column: &EditableStructureColumn) -> String {
     let data_type = column_data_type(dialect, column);
     let mut parts = vec![quote_ident(dialect, &column.name), data_type];
+    // QuestDB SQL Syntax: ```ALTER TABLE tableName ADD COLUMN [IF NOT EXISTS] columnName typeDef```
+    if dialect == StructureDialect::Questdb {
+        parts.insert(0, "IF NOT EXISTS".to_string());
+        return parts.join(" ");
+    }
     if !column.is_nullable && !is_oracle_like(dialect) && dialect != StructureDialect::ClickHouse {
         parts.push("NOT NULL".to_string());
     }
@@ -74,6 +79,9 @@ pub(super) fn column_data_type(dialect: StructureDialect, column: &EditableStruc
     if dialect == StructureDialect::ManticoreSearch {
         return manticore_column_type(column);
     }
+    if dialect == StructureDialect::Questdb {
+        return questdb_column_type(column);
+    }
     normalize_column_data_type(dialect, &column.data_type)
 }
 
@@ -186,3 +194,22 @@ pub(super) fn unwrap_clickhouse_nullable_type(data_type: &str) -> String {
         trimmed.to_string()
     }
 }
+
+/// QuestDB 类型处理
+/// geohash, decimal 这2种类型才能带()
+pub(super) fn questdb_column_type(column: &EditableStructureColumn) -> String {
+    let data_type = column.data_type.trim().to_ascii_lowercase();
+    let length_types: [&str; 2] = ["geohash", "decimal"];
+    match data_type.find('(') {
+        Some(pos) => {
+            let base_type = &data_type[..pos];
+            let params = &data_type[pos..];
+            if length_types.contains(&base_type) {
+                format!("{}{}", base_type, params)
+            } else {
+                base_type.to_string()
+            }
+        }
+        None => data_type,
+    }
+}

crates/dbx-core/src/table_structure_sql/columns.rs

@@ -1,8 +1,8 @@
 use super::column_alter::{
     build_clickhouse_existing_column_sql, build_h2_existing_column_sql, build_informix_existing_column_sql,
     build_mysql_existing_column_sql, build_oracle_like_existing_column_sql, build_postgres_existing_column_sql,
-    build_sqlite_existing_column_sql, build_sqlserver_existing_column_sql, has_column_extra_change,
-    has_existing_column_attribute_change,
+    build_questdb_existing_column_sql, build_sqlite_existing_column_sql, build_sqlserver_existing_column_sql,
+    has_column_extra_change, has_existing_column_attribute_change,
 };
 use super::column_format::column_definition;
 use super::comments::build_sqlserver_column_comment_sql;
@@ -120,6 +120,7 @@ pub(super) fn build_column_sql(options: &TableStructureSqlOptions, warnings: &mu
                 &options.table_name,
             )),
             StructureDialect::Sqlite => statements.extend(build_sqlite_existing_column_sql(&table, column, warnings)),
+            StructureDialect::Questdb => statements.extend(build_questdb_existing_column_sql(&table, column)),
             _ => warnings.push(format!("Editing existing columns is not supported for {database_label} yet.")),
         }
     }

crates/dbx-core/src/table_structure_sql/dialect.rs

@@ -13,6 +13,7 @@ pub(super) enum StructureDialect {
     ClickHouse,
     ManticoreSearch,
     Informix,
+    Questdb,
     Unsupported,
 }
 
@@ -116,6 +117,23 @@ pub(super) fn capabilities_for(database_type: Option<DatabaseType>) -> TableStru
             alter_primary_key: true,
             ..base
         },
+        Some(DatabaseType::Questdb) => TableStructureCapabilities {
+            dialect: StructureDialect::Questdb,
+            add_column: true,
+            drop_column: true,
+            rename_column: true,
+            alter_existing_column: true,
+            reorder_column: false,
+            comment: false,
+            create_index: false,
+            drop_index: false,
+            rebuild_index: false,
+            index_type: false,
+            index_include: false,
+            index_filter: false,
+            index_comment: false,
+            alter_primary_key: false,
+        },
         Some(DatabaseType::Redshift | DatabaseType::Vertica) => TableStructureCapabilities {
             dialect: StructureDialect::Postgres,
             add_column: true,
@@ -254,6 +272,7 @@ pub(super) fn dialect_label(dialect: StructureDialect) -> String {
         StructureDialect::ClickHouse => "clickhouse",
         StructureDialect::ManticoreSearch => "manticoresearch",
         StructureDialect::Informix => "informix",
+        StructureDialect::Questdb => "questdb",
         StructureDialect::Unsupported => "this database",
     }
     .to_string()
@@ -272,6 +291,7 @@ pub(super) fn database_type_for_dialect(dialect: StructureDialect) -> Option<Dat
         StructureDialect::ClickHouse => Some(DatabaseType::ClickHouse),
         StructureDialect::ManticoreSearch => Some(DatabaseType::ManticoreSearch),
         StructureDialect::Informix => Some(DatabaseType::Informix),
+        StructureDialect::Questdb => Some(DatabaseType::Questdb),
         StructureDialect::Unsupported => None,
     }
 }

crates/dbx-core/src/table_structure_sql/util.rs

@@ -18,7 +18,9 @@ pub(super) fn qualified_table(dialect: StructureDialect, schema: Option<&str>, t
 
 pub(super) fn quote_ident(dialect: StructureDialect, name: &str) -> String {
     match dialect {
-        StructureDialect::Mysql | StructureDialect::ManticoreSearch => format!("`{}`", name.replace('`', "``")),
+        StructureDialect::Mysql | StructureDialect::ManticoreSearch | StructureDialect::Questdb => {
+            format!("`{}`", name.replace('`', "``"))
+        }
         StructureDialect::SqlServer => format!("[{}]", name.replace(']', "]]")),
         StructureDialect::Informix if is_simple_informix_identifier(name) => name.to_string(),
         _ => format!("\"{}\"", name.replace('"', "\"\"")),