🔴Engine

Engine is initialized with Snowflake connection and config. It is used to build, format and execute DDL commands by resolvers.

Engine is represented by class SnowDDLEngine, which is located in engine.py.

One engine is expected to be reused by multiple resolvers executed in the correct order.

Engine settings

Settings are represented by class SnowDDLSettings.

You may find the most recent version of settings in settings.py.

Settings starting with execute_ control the execution behaviour. If value is True, DDL commands of this type will be executed. If value is False, commands will be "suggested" (dumped for manual execution) instead.

Engine context

Engine collects information about Snowflake connection context during initialization.

You should check which context properties are available in context.py.

Methods

• __init__(connection: SnowflakeConnection, config: SnowDDLConfig, settings: SnowDDLSettings) Initialize engine with Snowflake connection, config and settings.

• format(sql, params=None) Formats SQL query using SnowDDL formatter.

• query_builder() Create sand returns new query builder.

• describe_meta(sql, params=None) Describes SQL query, compiles it without actually executing and returns information about result columns. If SQL query cannot be compiled, throws an exception.

• execute_meta(sql, params=None) Executes SQL query returning metadata information, usually SHOW commands.

• execute_context_ddl(sql, params=None) Executes DDL command which is used to initialize the current context. It is normally used to create technical role for env prefix feature.

• execute_safe_ddl(sql, params=None, condition=True) Executes DDL command which is classified as "safe", usually CREATE. Optionally checks the expression in condition argument and executes command only if expression is True. Otherwise, it only "suggests" DDL command.

• execute_unsafe_ddl(sql, params=None, condition=True) Executes DDL command which is classified as "unsafe", usually ALTER, DROP. Optionally checks the expression in condition argument and executes command only if expression is True. Otherwise, it only "suggests" DDL command.

Properties

• .connection (SnowflakeConnection);

• .config (SnowDDLConfig);

• .settings (SnowDDLSettings);

• .logger (Logger) - pre-initialized logger with name snowddl.engine;

• .executor (ThreadPoolExecutor) - pre-initialized pool executor;

• .executed_ddl (list) - list of raw DDL commands which were executed by engine;

  • {items} (str) - SQL query;

• .suggested_ddl (list) - list of raw DDL commands which were suggested for manual execution;

  • {items} (str) - SQL query;

• .context (SnowDDLContext) - pre-initialized context information (version, edition, current warehouse, etc.) extracted from Snowflake account;

• .schema_cache (SnowDDLSchemaCache) - pre-initialized cache with databases and schemas, used to reduce the number of metadata queries performed by resolvers;