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The website is moving to pgloader.org and readthedocs.io is going to be integrated. Let's see what happens. The docs build fine locally with the sphinx tools and the docs/Makefile. Having separate files for the documentation should help ease the maintenance and add new topics, such as support for Common Lisp Hackers level docs, which are currently missing.
160 lines
4.7 KiB
ReStructuredText
160 lines
4.7 KiB
ReStructuredText
Migrating a MS SQL Database to PostgreSQL
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=========================================
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This command instructs pgloader to load data from a MS SQL database.
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Automatic discovery of the schema is supported, including build of the
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indexes, primary and foreign keys constraints.
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Here's an example::
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load database
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from mssql://user@host/dbname
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into postgresql:///dbname
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including only table names like 'GlobalAccount' in schema 'dbo'
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set work_mem to '16MB', maintenance_work_mem to '512 MB'
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before load do $$ drop schema if exists dbo cascade; $$;
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The `mssql` command accepts the following clauses and options.
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MS SQL Database Source Specification: FROM
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------------------------------------------
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Connection string to an existing MS SQL database server that listens and
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welcome external TCP/IP connection. As pgloader currently piggybacks on the
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FreeTDS driver, to change the port of the server please export the `TDSPORT`
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environment variable.
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MS SQL Database Migration Options: WITH
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---------------------------------------
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When loading from a `MS SQL` database, the same options as when loading a
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`MySQL` database are supported. Please refer to the MySQL section. The
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following options are added:
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- *create schemas*
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When this option is listed, pgloader creates the same schemas as found
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on the MS SQL instance. This is the default.
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- *create no schemas*
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When this option is listed, pgloader refrains from creating any schemas
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at all, you must then ensure that the target schema do exist.
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MS SQL Database Casting Rules
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-----------------------------
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CAST
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^^^^
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The cast clause allows to specify custom casting rules, either to overload
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the default casting rules or to amend them with special cases.
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Please refer to the MySQL CAST clause for details.
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MS SQL Partial Migration
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------------------------
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INCLUDING ONLY TABLE NAMES LIKE
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Introduce a comma separated list of table name patterns used to limit the
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tables to migrate to a sublist. More than one such clause may be used, they
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will be accumulated together.
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Example::
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including only table names lile 'GlobalAccount' in schema 'dbo'
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EXCLUDING TABLE NAMES LIKE
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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Introduce a comma separated list of table name patterns used to exclude
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table names from the migration. This filter only applies to the result of
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the *INCLUDING* filter.
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::
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excluding table names matching 'LocalAccount' in schema 'dbo'
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MS SQL Schema Transformations
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-----------------------------
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ALTER SCHEMA '...' RENAME TO '...'
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Allows to rename a schema on the flight, so that for instance the tables
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found in the schema 'dbo' in your source database will get migrated into the
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schema 'public' in the target database with this command::
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alter schema 'dbo' rename to 'public'
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ALTER TABLE NAMES MATCHING ... IN SCHEMA '...'
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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See the MySQL explanation for this clause above. It works the same in the
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context of migrating from MS SQL, only with the added option to specify the
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name of the schema where to find the definition of the target tables.
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The matching is done in pgloader itself, with a Common Lisp regular
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expression lib, so doesn't depend on the *LIKE* implementation of MS SQL,
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nor on the lack of support for regular expressions in the engine.
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MS SQL Driver setup and encoding
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--------------------------------
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pgloader is using the `FreeTDS` driver, and internally expects the data to
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be sent in utf-8. To achieve that, you can configure the FreeTDS driver with
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those defaults, in the file `~/.freetds.conf`::
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[global]
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tds version = 7.4
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client charset = UTF-8
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Default MS SQL Casting Rules
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----------------------------
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When migrating from MS SQL the following Casting Rules are provided:
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Numbers::
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type tinyint to smallint
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type float to float using float-to-string
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type real to real using float-to-string
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type double to double precision using float-to-string
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type numeric to numeric using float-to-string
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type decimal to numeric using float-to-string
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type money to numeric using float-to-string
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type smallmoney to numeric using float-to-string
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Texts::
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type char to text drop typemod
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type nchat to text drop typemod
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type varchar to text drop typemod
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type nvarchar to text drop typemod
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type xml to text drop typemod
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Binary::
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type binary to bytea using byte-vector-to-bytea
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type varbinary to bytea using byte-vector-to-bytea
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Date::
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type datetime to timestamptz
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type datetime2 to timestamptz
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Others::
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type bit to boolean
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type hierarchyid to bytea
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type geography to bytea
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type uniqueidentifier to uuid using sql-server-uniqueidentifier-to-uuid
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