feat: postgres integration - create database (#932)

1. Add support for creating database
```
CREATE DATABASE db
WITH ENGINE = "postgres",
PARAMETERS = {
    "user": "user",
    "password": "password",
    "host": "127.0.0.1",
    "port": "5432",
    "database": "demo"
};
```
2. Persist the info in the catalog
3. Todo: Verify if the provided info is valid - next PR

evadb/catalog/catalog_manager.py

@@ -33,6 +33,7 @@
 )
 from evadb.catalog.models.utils import (
     ColumnCatalogEntry,
+    DatabaseCatalogEntry,
     IndexCatalogEntry,
     TableCatalogEntry,
     UdfCacheCatalogEntry,
@@ -45,6 +46,7 @@
     truncate_catalog_tables,
 )
 from evadb.catalog.services.column_catalog_service import ColumnCatalogService
+from evadb.catalog.services.database_catalog_service import DatabaseCatalogService
 from evadb.catalog.services.index_catalog_service import IndexCatalogService
 from evadb.catalog.services.table_catalog_service import TableCatalogService
 from evadb.catalog.services.udf_cache_catalog_service import UdfCacheCatalogService
@@ -70,6 +72,7 @@ def __init__(self, db_uri: str, config: ConfigurationManager):
         self._sql_config = SQLConfig(db_uri)
         self._config = config
         self._bootstrap_catalog()
+        self._db_catalog_service = DatabaseCatalogService(self._sql_config.session)
         self._table_catalog_service = TableCatalogService(self._sql_config.session)
         self._column_service = ColumnCatalogService(self._sql_config.session)
         self._udf_service = UdfCatalogService(self._sql_config.session)
@@ -121,6 +124,48 @@ def _clear_catalog_contents(self):
         # clean up the dataset, index, and cache directories
         cleanup_storage(self._config)
 
+    "Database catalog services"
+
+    def insert_database_catalog_entry(self, name: str, engine: str, params: dict):
+        """A new entry is persisted in the database catalog."
+
+        Args:
+            name: database name
+            engine: engine name
+            params: required params as a dictionary for the database
+        """
+        self._db_catalog_service.insert_entry(name, engine, params)
+
+    def get_database_catalog_entry(self, database_name: str) -> DatabaseCatalogEntry:
+        """
+        Returns the database catalog entry for the given database_name
+        Arguments:
+            database_name (str): name of the database
+
+        Returns:
+            DatabaseCatalogEntry
+        """
+
+        table_entry = self._db_catalog_service.get_entry_by_name(database_name)
+
+        return table_entry
+
+    def delete_database_catalog_entry(
+        self, database_entry: DatabaseCatalogEntry
+    ) -> bool:
+        """
+        This method deletes the database from  catalog.
+
+        Arguments:
+           database_entry: database catalog entry to remove
+
+        Returns:
+           True if successfully deleted else False
+        """
+        # todo: do we need to remove also the associated tables etc or that will be
+        # taken care by the underlying db
+        return self._db_catalog_service.delete_entry(database_entry)
+
     "Table catalog services"
 
     def insert_table_catalog_entry(

evadb/catalog/catalog_utils.py

@@ -38,19 +38,6 @@
 from evadb.parser.create_statement import ColConstraintInfo, ColumnDefinition
 from evadb.utils.generic_utils import get_str_hash, remove_directory_contents
 
-CATALOG_TABLES = [
-    "column_catalog",
-    "table_catalog",
-    "depend_column_and_udf_cache",
-    "udf_cache",
-    "udf_catalog",
-    "depend_udf_and_udf_cache",
-    "index_catalog",
-    "udfio_catalog",
-    "udf_cost_catalog",
-    "udf_metadata_catalog",
-]
-
 
 def is_video_table(table: TableCatalogEntry):
     return table.table_type == TableType.VIDEO_DATA

evadb/catalog/models/database_catalog.py

@@ -0,0 +1,47 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from sqlalchemy import Column, String
+
+from evadb.catalog.models.base_model import BaseModel
+from evadb.catalog.models.utils import DatabaseCatalogEntry, TextPickleType
+
+
+class DatabaseCatalog(BaseModel):
+    """The `DatabaseCatalog` catalog stores information about all databases.
+    `_row_id:` an autogenerated unique identifier.
+    `_name:` the database name.
+    `_engine:` database engine
+    `_param:` parameters specific to the database engine
+    """
+
+    __tablename__ = "database_catalog"
+
+    _name = Column("name", String(100), unique=True)
+    _engine = Column("engine", String(100))
+    _params = Column("params", TextPickleType())
+
+    def __init__(self, name: str, engine: str, params: dict):
+        self._name = name
+        self._engine = engine
+        self._params = params
+
+    def as_dataclass(self) -> "DatabaseCatalogEntry":
+        return DatabaseCatalogEntry(
+            row_id=self._row_id,
+            name=self._name,
+            engine=self._engine,
+            params=self._params,
+        )

evadb/catalog/models/utils.py

@@ -13,11 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import contextlib
+import json
 from dataclasses import dataclass, field
 from typing import List, Tuple
 
 import sqlalchemy
 from sqlalchemy.engine import Engine
+from sqlalchemy.types import TypeDecorator
 from sqlalchemy_utils import create_database, database_exists
 
 from evadb.catalog.catalog_type import (
@@ -31,6 +33,25 @@
 from evadb.utils.logging_manager import logger
 
 
+class TextPickleType(TypeDecorator):
+    """Used to handle serialization and deserialization to Text
+    https://stackoverflow.com/questions/1378325/python-dicts-in-sqlalchemy
+    """
+
+    impl = sqlalchemy.String(1024)
+
+    def process_bind_param(self, value, dialect):
+        if value is not None:
+            value = json.dumps(value)
+
+        return value
+
+    def process_result_value(self, value, dialect):
+        if value is not None:
+            value = json.loads(value)
+        return value
+
+
 def init_db(engine: Engine):
     """Create database if doesn't exist and create all tables."""
     if not database_exists(engine.url):
@@ -209,3 +230,22 @@ def _to_str(col):
             "impl": self.impl_file_path,
             "metadata": self.metadata,
         }
+
+
+@dataclass(unsafe_hash=True)
+class DatabaseCatalogEntry:
+    """Dataclass representing an entry in the `DatabaseCatalog`.
+    This is done to ensure we don't expose the sqlalchemy dependencies beyond catalog service. Further, sqlalchemy does not allow sharing of objects across threads.
+    """
+
+    name: str
+    engine: str
+    params: dict
+    row_id: int = None
+
+    def display_format(self):
+        return {
+            "name": self.name,
+            "engine": self.engine,
+            "params": self.params,
+        }

evadb/catalog/services/database_catalog_service.py

@@ -0,0 +1,83 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from sqlalchemy.orm import Session
+from sqlalchemy.sql.expression import select
+
+from evadb.catalog.models.database_catalog import DatabaseCatalog
+from evadb.catalog.models.utils import DatabaseCatalogEntry
+from evadb.catalog.services.base_service import BaseService
+from evadb.utils.errors import CatalogError
+from evadb.utils.logging_manager import logger
+
+
+class DatabaseCatalogService(BaseService):
+    def __init__(self, db_session: Session):
+        super().__init__(DatabaseCatalog, db_session)
+
+    def insert_entry(
+        self,
+        name: str,
+        engine: str,
+        params: dict,
+    ):
+        try:
+            db_catalog_obj = self.model(
+                name=name,
+                engine=engine,
+                params=params,
+            )
+            db_catalog_obj = db_catalog_obj.save(self.session)
+
+        except Exception as e:
+            logger.exception(
+                f"Failed to insert entry into database catalog with exception {str(e)}"
+            )
+            raise CatalogError(e)
+
+    def get_entry_by_name(self, database_name: str) -> DatabaseCatalogEntry:
+        """
+        Get the table catalog entry with given table name.
+        Arguments:
+            database_name  (str): Database name
+        Returns:
+            DatabaseCatalogEntry - catalog entry for given database name
+        """
+        entry = self.session.execute(
+            select(self.model).filter(self.model._name == database_name)
+        ).scalar_one_or_none()
+        if entry:
+            return entry.as_dataclass()
+        return entry
+
+    def delete_entry(self, database_entry: DatabaseCatalogEntry):
+        """Delete database from the catalog
+        Arguments:
+            database  (DatabaseCatalogEntry): database to delete
+        Returns:
+            True if successfully removed else false
+        """
+        try:
+            db_catalog_obj = self.session.execute(
+                select(self.model).filter(self.model._row_id == database_entry.row_id)
+            ).scalar_one_or_none()
+            db_catalog_obj.delete(self.session)
+            return True
+        except Exception as e:
+            err_msg = (
+                f"Delete database failed for {database_entry} with error {str(e)}."
+            )
+            logger.exception(err_msg)
+            raise CatalogError(err_msg)

evadb/catalog/sql_config.py

@@ -26,6 +26,7 @@
 CATALOG_TABLES = [
     "column_catalog",
     "table_catalog",
+    "database_catalog",
     "depend_column_and_udf_cache",
     "udf_cache",
     "udf_catalog",

evadb/executor/create_database_executor.py

@@ -0,0 +1,48 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import pandas as pd
+
+from evadb.database import EvaDBDatabase
+from evadb.executor.abstract_executor import AbstractExecutor
+from evadb.models.storage.batch import Batch
+from evadb.parser.create_statement import CreateDatabaseStatement
+from evadb.utils.logging_manager import logger
+
+
+class CreateDatabaseExecutor(AbstractExecutor):
+    def __init__(self, db: EvaDBDatabase, node: CreateDatabaseStatement):
+        super().__init__(db, node)
+
+    def exec(self, *args, **kwargs):
+        # todo handle if_not_exists
+
+        logger.debug(
+            f"Trying to connect to the provided engine {self.node.engine} with params {self.node.param_dict}"
+        )
+        # todo handle if the provided database params are valid
+
+        logger.debug(f"Creating database {self.node}")
+
+        self.catalog().insert_database_catalog_entry(
+            self.node.database_name, self.node.engine, self.node.param_dict
+        )
+
+        yield Batch(
+            pd.DataFrame(
+                [
+                    f"The database {self.node.database_name} has been successfully created."
+                ]
+            )
+        )

evadb/executor/plan_executor.py

@@ -12,11 +12,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Iterator
+from typing import Iterator, Union
 
 from evadb.database import EvaDBDatabase
 from evadb.executor.abstract_executor import AbstractExecutor
 from evadb.executor.apply_and_merge_executor import ApplyAndMergeExecutor
+from evadb.executor.create_database_executor import CreateDatabaseExecutor
 from evadb.executor.create_executor import CreateExecutor
 from evadb.executor.create_index_executor import CreateIndexExecutor
 from evadb.executor.create_udf_executor import CreateUDFExecutor
@@ -46,6 +47,8 @@
 from evadb.executor.union_executor import UnionExecutor
 from evadb.executor.vector_index_scan_executor import VectorIndexScanExecutor
 from evadb.models.storage.batch import Batch
+from evadb.parser.create_statement import CreateDatabaseStatement
+from evadb.parser.statement import AbstractStatement
 from evadb.plan_nodes.abstract_plan import AbstractPlan
 from evadb.plan_nodes.types import PlanOprType
 from evadb.utils.logging_manager import logger
@@ -65,7 +68,9 @@ def __init__(self, evadb: EvaDBDatabase, plan: AbstractPlan):
         self._db = evadb
         self._plan = plan
 
-    def _build_execution_tree(self, plan: AbstractPlan) -> AbstractExecutor:
+    def _build_execution_tree(
+        self, plan: Union[AbstractPlan, AbstractStatement]
+    ) -> AbstractExecutor:
         """build the execution tree from plan tree
 
         Arguments:
@@ -78,6 +83,10 @@ def _build_execution_tree(self, plan: AbstractPlan) -> AbstractExecutor:
         if plan is None:
             return root
 
+        # First handle cases when the plan is actually a parser statement
+        if isinstance(plan, CreateDatabaseStatement):
+            return CreateDatabaseExecutor(db=self._db, node=plan)
+
         # Get plan node type
         plan_opr_type = plan.opr_type