Snowflake Database (via JDBC) - Import

Bridge Requirements

This bridge:

requires Internet access to https://repo.maven.apache.org/maven2/ and/or other tool sites to download drivers into <TDC_HOME>/data/download/MIMB/.

Bridge Specifications

Vendor	Snowflake
Tool Name	Snowflake Database
Tool Version	1 to current
Tool Web Site	https://www.snowflake.com/
Supported Methodology	[Relational Database] Multi-Model, Data Store (Physical Data Model, Stored Procedure Expression Parsing) via JDBC API
Data Profiling
Incremental Harvesting
Multi-Model Harvesting
Remote Repository Browsing for Model Selection

SPECIFICATIONS
Tool: Snowflake / Snowflake Database version 1 to current via JDBC API
See https://www.snowflake.com/
Metadata: [Relational Database] Multi-Model, Data Store (Physical Data Model, Stored Procedure Expression Parsing)
Component: JdbcSnowflake version 11.2.0

DISCLAIMER
This import bridge requires internet access to download third-party libraries:
- such as https://repo.maven.apache.org/maven2/ to download open source third-party libraries,
- and more sites for other third-party software such as database specific JDBC drivers.

The downloaded third-party libraries are stored into $HOME/data/download/MIMB/
- If HTTPS fails, the import bridge then tries with HTTP.
- If a proxy is used to access internet, you must configure that proxy in the JRE (see the -j option in the Miscellaneous parameter).
- If the import bridge does not have full access to internet, that $HOME/data/download/MIMB/ directory can be copied from another server with internet access where the command $HOME/bin/MIMB.sh (or .bat) -d can be used to download all third-party libraries used by all bridges at once.

By running this import bridge, you hereby acknowledge responsibility for the license terms and any potential security vulnerabilities from these downloaded third-party software libraries.

OVERVIEW
This import bridge uses a JDBC connection to a SNOWFLAKE database server to extract all its metadata (e.g. Schemas, Tables, Columns, Data Types, Iceberg tables) and parse any SQL (e.g. Views, Stored Procedures) to produce the data flow lineage.

This import bridge imports the database server metadata as multi models with one model per schema. Further imports (incremental harvesting) will detect changes in schema to only import changed Schemas (reusing already harvested unchanged Schemas).

REQUIREMENTS
Minimal supported database version is 8.4.

See the Driver Location parameter for any JDBC driver requirements.

See the PERMISSIONS section below.

AUTHENTICATION
n/a

PERMISSIONS
Any import bridge is warranted to be read only and only extracts metadata. Therefore the user of this import bridge requires much less permissions than classic users needing to read/write data.

In case of the Snowflake Database:
The User should have a security Role with the following privileges for the current and future databases, schemas, tables, views, materialized views, functions, procedures, sequences, streams, tasks, stages, and pipes:
grant usage on warehouse <warehouse_name> to role <role_name>;
grant usage on database <database_name> to role <role_name>;
grant usage on all schemas in database <database_name> to role <role_name>;
grant references on all tables in schema <schema_name> to role <role_name>;
grant references on all views in schema <schema_name> to role <role_name>;
grant references on all materialized views in schema <schema_name> to role <role_name>;
grant usage on all functions in schema <schema_name> to role <role_name>;
grant usage on all procedures in schema <schema_name> to role <role_name>;
grant usage on all sequences in schema <schema_name> to role <role_name>;
grant SELECT on all streams in schema <schema_name> to role <role_name>;
grant monitor on all tasks in schema <schema_name> to role <role_name>;
grant usage on all stages in schema <schema_name> to role <role_name>;
grant monitor on pipe <pipe_name> to role <role_name>;
grant usage on external volume <external_volume_name> TO <role_name>;
grant monitor on all dynamic tables in schema <schema_name> TO <role_name>;

grant usage on future schemas in database <database_name> to role <role_name>;
grant references on future tables in schema <schema_name> to role <role_name>;
grant references on future views in schema <schema_name> to role <role_name>;
grant references on future materialized views in schema <schema_name> to role <role_name>;
grant usage on future functions in schema <schema_name> to role <role_name>;
grant usage on future procedures in schema <schema_name> to role <role_name>;
grant usage on future sequences in schema <schema_name> to role <role_name>;
grant SELECT on future streams in schema <schema_name> to role <role_name>;
grant monitor on future tasks in schema <schema_name> to role <role_name>;
grant usage on future stages in schema <schema_name> to role <role_name>;
grant monitor on future pipes in schema <schema_name> to role <role_name>;
grant monitor on future dynamic tables in schema <schema_name> TO <role_name>;

When the User is not privileged to get function and procedure definitions in bulk, specify the -describe.function option in the Miscellaneous parameter to extract these definitions using DESCRIBE FUNCTION commands. It will slow down the import when there are a lot of functions and procedures.

FREQUENTLY ASKED QUESTIONS
Q: How to overcome this error "SqlException was thrown: SQL error (Cannot perform SELECT. This session does not have a current database."?
A: Review the Host parameter for correct syntax of your host name, as there is an error present.

LIMITATIONS
Refer to the current general known limitations at MIMB Known Limitations or bundled in Documentation/ReadMe/MIMBKnownLimitations.html

SUPPORT
Provide a troubleshooting package with:
- the debug log (can be set in the UI or in conf/conf.properties with MIR_LOG_LEVEL=6)
- the metadata backup if available (can be set in the Miscellaneous parameter with -backup option, although this common option is not implemented on all bridges for technical reasons).

Bridge Parameters

Parameter Name

Description

Type

Values

Default

Scope

Driver location

The file directory where the JDBC driver files are located. When the value is empty (default), the bridge tries to download the driver files from Maven.

The default driver class name is 'net.snowflake.client.jdbc.SnowflakeDriver'.

If the driver specified has a different class name, specify that name using the -driver.className option in the Miscellaneous bridge parameter.

DIRECTORY

Account

The Snowflake account identifier or JDBC connection string.

The account identifier (or locator) uniquely determines the Snowflake account within your organization (e.g. myorg-account123).
To learn more about Snowflake account identifiers, please see https://docs.snowflake.com/en/user-guide/admin-account-identifier.html#

The JDBC connection string allows you to specify the Snowflake account identifier and additional connection parameters. For example,
jdbc:snowflake://myorg-account123.snowflakecomputing.com/?warehouse=mywh&db=mydb
You should use the User and Password parameters to specify the authentication information.
To learn more about the Snowflake JDBC Driver Connection String, please see https://docs.snowflake.com/en/developer-guide/jdbc/jdbc-configure#jdbc-driver-connection-string

STRING

localhost

Mandatory

Warehouse

The name of the warehouse instance to import.

STRING

Mandatory

Databases

Names of databases you want to import. Separate names in the list with a semi-colon (;).

When you want to import all databases in the warehouse leave the parameter empty.

To specify the name of the database you would like to use for authentication, you may set the user default name space in Snowflake (e.g. ALTER USER myUser SET DEFAULT_NAMESPACE = CONNECTION_DB ;) or by specifying it under the Host parameter utilizing the JDBC connection string format (e.g. https://123.us-east-2.aws.snowflakecomputing.com/?db=CONNECTION_DB).

You can use SQL LIKE patterns to identify names of databases. See the Schema parameter documentation for details.

REPOSITORY_SUBSET

User

The user name used by JDBC to connect to the database server.

This parameter is ignored if the Host parameter is based on a fully qualified JDBC connection string that includes the user name.

Refer to the PERMISSIONS section of this import bridge's main documentation.

STRING

Password

The user password used by JDBC to connect to the database server.

PASSWORD

Schemas

The subset of schemas to import expressed as a semicolon separated list of schemas' names, e.g.
schema1; schema2

This parameter also supports the dot annotation in combination with * wildcards to enable specification of what groups of objects to import, e.g.
database1.schema1; database2.*;

All accessible user schemas are imported if that list is empty.

All system schemas (e.g. SysAdmin) and objects are ignored by default. If system schemas are needed, use the Miscellaneous parameter option -system.objects.import.

Schema name patterns using the syntax rules used by the LIKE operator in SQL:

- Inclusion syntax:
using % or *, e.g.
A%; %B; %C%; D
- start with A or
- end with B or
- contain C or
- equal D

- Exclusion syntax:
using NOT, e.g.
A%; %B; NOT %SYS; NOT 'SYS%'
- WHERE (name like A% or name like %B)
- and (name NOT like %SYS)
- and (name NOT like 'SYS%')

- Special characters:
^ $ * + ? | \ ( ) [ ] { } whitespace
enclose this name in square brackets and escape special characters, e.g.
OneWord%; [Two\sWords.*]; [Dollar\$]

REPOSITORY_SUBSET

Tables

The subset of "Tables" to import expressed as a semicolon separated list of objects in schemas, like table, view, function, e.g.
table1; table2; view1; function1

This parameter also supports the [database.][schema.]table dot annotation in combination with * wildcards to enable specification of what groups of objects to import, e.g.
database1.schema1.table1; database1.*.table2; database1.schema3.*;

All user objects that the bridge supports are imported if that list is empty.

All system tables (e.g. SysAdmin) and objects are ignored by default. If system tables are needed, use the Miscellaneous parameter option -system.objects.import.

Table name patterns using a SQL like expression syntax:

- Inclusion syntax:
using % or *, e.g.
A%; %B; %C%; D
- start with A or
- end with B or
- contain C or
- equal D

- Exclusion syntax:
using NOT, e.g.
A%; %B; NOT %SYS; NOT 'SYS%'
- WHERE (name like A% or name like %B)
- and (name NOT like %SYS)
- and (name NOT like 'SYS%')

- Special characters:
^ $ * + ? | \ ( ) [ ] { } whitespace
enclose this name in square brackets and escape special characters, e.g.
OneWord%; [Two\sWords.*]; [Dollar\$]

STRING

Import indexes

Controls the import of Indexes:

'False'
Indexes are not imported

'True'
Indexes are imported

BOOLEAN

False

True

False

Stored procedure details

Controls the amount of details imported from stored procedures:

'Signature'
The name and parameters of stored procedures

'Code, signature'
The above plus code

'Lineage, code, signature'
The above plus data lineage derived from the code

'None'
stored procedure details are not included.

ENUMERATED

None

Signature

Code, signature

Lineage, code, signature

Signature

Miscellaneous

INTRODUCTION
Specify miscellaneous options starting with a dash and optionally followed by parameters, e.g.
-connection.cast MyDatabase1="MICROSOFT SQL SERVER"
Some options can be used multiple times if applicable, e.g.
-connection.rename NewConnection1=OldConnection1 -connection.rename NewConnection2=OldConnection2;
As the list of options can become a long string, it is possible to load it from a file which must be located in ${MODEL_BRIDGE_HOME}\data\MIMB\parameters and have the extension .txt. In such case, all options must be defined within that file as the only value of this parameter, e.g.
ETL/Miscellaneous.txt

JAVA ENVIRONMENT OPTIONS
-java.memory <Java Memory's maximum size> (previously -m)

1G by default on 64bits JRE or as set in conf/conf.properties, e.g.
-java.memory 8G
-java.memory 8000M

-java.parameters <Java Runtime Environment command line options> (previously -j)

This option must be the last one in the Miscellaneous parameter as all the text after -java.parameters is passed "as is" to the JRE, e.g.
-java.parameters -Dname=value -Xms1G
The following option must be set when a proxy is used to access internet (this is critical to access https://repo.maven.apache.org/maven2/ and exceptionally a few other tool sites) in order to download the necessary third-party software libraries.
Note: The majority of proxies are concerned with encrypting (HTTPS) the outside (of the company) traffic and trust the inside traffic that can access proxy over HTTP. In this case, an HTTPS request reaches the proxy over HTTP where the proxy HTTPS-encrypts it.
-java.parameters -java.parameters -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 -Dhttp.proxyUser=user -Dhttp.proxyPassword=pass

MODEL IMPORT OPTIONS
-model.name <model name>

Override the model name, e.g.
-model.name "My Model Name"

-prescript <script name>

This option allows running a script before the bridge execution.
The script must be located in the bin directory (or as specified with M_SCRIPT_PATH in conf/conf.properties), and have .bat or .sh extension.
The script path must not include any parent directory symbol (..).
The script should return exit code 0 to indicate success, or another value to indicate failure.
For example:
-prescript "script.bat arg1 arg2"

-postscript <script name>

This option allows running a script after successful execution of the bridge.
The script must be located in the bin directory (or as specified with M_SCRIPT_PATH in conf/conf.properties), and have .bat or .sh extension.
The script path must not include any parent directory symbol (..).
The script should return exit code 0 to indicate success, or another value to indicate failure.
For example:
-postscript "script.bat arg1 arg2"

-cache.clear

Clears the cache before the import, and therefore will run a full import without incremental harvesting.

If the model was not changed and the -cache.clear parameter is not used (incremental harvesting), then a new version will not be created.
If the model was not changed and the -cache.clear parameter is set (full source import instead of incremental), then a new version will be created.

-backup <directory>

This option allows to save the bridge input metadata for further troubleshooting. The provided <directory> must be empty.

The primary use of this option is for data store import bridges, in particular JDBC based database import bridges.

Note that this option is not operational on some bridges including:
- File based import bridges (as such input files can be used instead)
- DI/BI repository import bridges (as the tool's repository native backup can be used instead)
- Some API based import bridges (e.g. COM based) for technical reasons.

DATA CONNECTION OPTIONS
Data Connections are produced by the import bridges typically from ETL/DI and BI tools to refer to the source and target data stores they use. These data connections are then used by metadata management tools to connect them (metadata stitching) to their actual data stores (e.g. databases, file system, etc.) in order to produce the full end to end data flow lineage and impact analysis. The name of each data connection is unique by import model. The data connection names used within DI/BI design tools are used when possible, otherwise connection names are generated to be short but meaningful such as the database / schema name, the file system path, or Uniform Resource Identifier (URI). The following option allows to manipulate connections. These options replaces the legacy options -c, -cd, and -cs.

-connection.cast ConnectionName=ConnectionType

Casts a generic database connection (e.g. ODBC/JDBC) to a precise database type (e.g. ORACLE) for SQL Parsing, e.g.
-connection.cast "My Database"="MICROSOFT SQL SERVER".
The list of supported data store connection types includes:
ACCESS
APACHE CASSANDRA
DB2/UDB
DENODO
GOOGLE BIGQUERY
HIVE
MYSQL
NETEZZA
ORACLE
POSTGRESQL
PRESTO
REDSHIFT
SALESFORCE
SAP HANA
SNOWFLAKE
MICROSOFT SQL AZURE
MICROSOFT SQL SERVER
SYBASE SQL SERVER
SYBASE AS ENTERPRISE
TERADATA
VECTORWISE
HP VERTICA

-connection.rename OldConnection=NewConnection

Renames an existing connection to a new name, e.g.
-connection.rename OldConnectionName=NewConnectionName
Multiple existing database connections can be renamed and merged into one new database connection, e.g.
-connection.rename MySchema1=MyDatabase -connection.rename MySchema2=MyDatabase

-connection.split oldConnection.Schema1=newConnection

Splits a database connection into one or multiple database connections.
A single database connection can be split into one connection per schema, e.g.
-connection.split MyDatabase
All database connections can be split into one connection per schema, e.g.
-connection.split *
A database connection can be explicitly split creating a new database connection by appending a schema name to a database, e.g.
-connection.split MyDatabase.schema1=MySchema1

-connection.map SourcePath=DestinationPath

Maps a source path to destination path. This is useful for file system connections when different paths points to the same object (directory or file).
On Hadoop, a process can write into a CSV file specified with the HDFS full path, but another process reads from a Hive table implemented (external) by the same file specified using a relative path with default file name and extension, e.g.
-connection.map /user1/folder=hdfs://host:8020/users/user1/folder/file.csv
On Linux, a given directory (or file) like /data can be referred to by multiple symbolic links like /users/john and /users/paul, e.g.
-connection.map /data=/users/John -connection.map /data=/users/paul
On Windows, a given directory like C:\data can be referred to by multiple network drives like M: and N:, e.g.
-connection.map C:\data=M:\ -connection.map C:\data=N:\

-connection.casesensitive ConnectionName

Overrides the default case insensitive matching rules for the object identifiers inside the specified connection, provided the detected type of the data store by itself supports this configuration (e.g. Microsoft SQL Server, MySql etc.), e.g.
-connection.casesensitive "My Database"

-connection.level AggregationLevel

Specifies the aggregation level for the external connections, e.g.-connection.level catalog
The list of the supported values:
server
catalog
schema (default)

JDBC DATABASE OPTIONS
-system.objects.import (previously -s)

Imports all system objects (that are skipped by default).

-synonyms.ignore (previously -synonyms)

Ignores the synonyms when importing, therefore reducing the size of the model when a large number synonyms exist.

-data.dictionary.server <database identification name> (previously -server.name)

Sets a server name for the data dictionary to use for extracting tables and view definitions.
In a multitenant Container Database (CDB), the metadata for data dictionary tables and view definitions is stored only at the root level. However, each Pluggable Database (PDB) has its own set of data dictionary tables and views for the database objects contained in the PDB. It is possible that some dba_ views are not available because they are not applicable.

-driver.fetch.size <number of rows> (previously -f)

The database driver fetch size in number of rows, e.g.
-driver.fetch.size 100

-model.split (previously -multiModel)

Splits a large database model into multi models (e.g. one schema per model).
Warning: this is a system option managed by the application calling this import bridge and should not be set by users.

-driver.className

The full name (including the package name) of the Java class that implements the JDBC driver interface.

-describe.function

Extract function definitions using DESCRIBE FUNCTION commands for the user that does not have privileges to get these definitions in bulk. Can slow down the import when there are a lot of functions.

-external_tables

Extract external table metadata using system view external_tables

-show.columns

Extract column metadata using SHOW COLUMNS commands for the user that does not have privileges to get the column metadata in bulk. Can slow down the import when there are a lot of Schemas.

-network.timeout <milliseconds>

Specifies the number of milliseconds to wait for a response when interacting with the Snowflake service before returning an error.

STRING

Bridge Mapping

Meta Integration Repository (MIR) Metamodel (based on the OMG CWM standard)	"Snowflake Database (via JDBC)" Metamodel Jdbc	Mapping Comments

Name	Name
Attribute	Table Column
Comment	Comments on the column	If JDBC driver supports
InitialValue	Default value
Name	Name
Optional	Based on the nullable property	For Access databases, set to false only if the attribute is in a Unique Index
PhysicalName	Name
Position	Position	If position is not provided, the order in which the attributes are retrieved is used.
BaseType	Types
DataType	Data Type	See datatype conversion array
Length	Size
Name		The name is computed from the datatype
PhysicalName	Name
Scale	Maximum scale
Class	Table	of type "TABLE"
Comment	Comments on the table	If JDBC driver supports
CppClassType		Set to ENTITY
CppPersistent		Set to True
Name	Name
PhysicalName	Name
ClassDiagram	Schema	A class diagram is created for each package and contains all the elements of the package
DerivedType	Column	Table column, stored procedure column SQL View column or type
DataType	Data Type	See datatype conversion array
Length	Size
Name		The name is computed from the datatype
PhysicalName	Name
Scale	Decimal digits
UserDefined		True for Type
DesignPackage	Schema	A Package is created for each retrieved schema. If there is no schema a default package is created.
Name	Name	Set to "Schema" if there is no schema or the schema has no name.
SQLViewAttribute	View Column
Comment	Comments on the column	If JDBC driver supports
Name	Name
PhysicalName	Name
Position	Ordinal position
SQLViewEntity	Table	of type "VIEW"
Comment	Comments on the table	If JDBC driver supports
Name	Name
PhysicalName	Name
StoreModel	Catalog	The model is built using the elements contained in the catalog (e.g. the database for MS SQL server)
Name	Name	Set to "Catalog" if the catalog has no name.
Synonym	Table Synonym	If JDBC driver supports
Name	Name

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