README

The MySQL Parser to Google Cloud Spanner is a library for PHP, providing an easy way to migrate the data from MySQL to Google Cloud Spanner.

Install

Via Composer

$ composer require mgcosta/mysql-to-cloud-spanner

Usage Instructions

To use this toolkit, you will need an array of the columns from MySQL and the respective foreign keys / indexes.

The table array you can use the Describe from MySQL, the foreign keys you will need to do something like that.

use MgCosta\MysqlParser\Parser;

$schemaParser = new Parser();

$tableName = 'users';

$table = [
    [
        'Field' => 'id',
        'Type' => 'biginteger unsigned',
        'Null' => 'NO',
        'Key' => 'PRI',
        'Default' => null,
        'Extra' => 'auto_increment'
    ],
    [
        'Field' => 'name',
        'Type' => 'varchar(255)',
        'Null' => 'NO',
        'Key' => '',
        'Default' => null,
        'Extra' => ''
    ],
    [
        'Field' => 'email',
        'Type' => 'varchar(255)',
        'Null' => 'NO',
        'Key' => 'UNI',
        'Default' => null,
        'Extra' => ''
    ],
    [
        'Field' => 'password',
        'Type' => 'varchar(255)',
        'Null' => 'NO',
        'Key' => '',
        'Default' => null,
        'Extra' => ''
    ]
];

$keys = [
    [
        'TABLE_NAME' => 'users',
        'COLUMN_NAME' => 'id',
        'CONSTRAINT_NAME' => 'PRIMARY',
        'REFERENCED_TABLE_NAME' => null,
        'REFERENCED_COLUMN_NAME' => null
    ],
    [
        'TABLE_NAME' => 'users',
        'COLUMN_NAME' => 'email',
        'CONSTRAINT_NAME' => 'users_email_unique',
        'REFERENCED_TABLE_NAME' => null,
        'REFERENCED_COLUMN_NAME' => null
    ]
];

$ddl = $schemaParser->setTableName($tableName)
                    ->setDescribedTable($table)
                    ->setKeys($keys)
                    ->toDDL();
                    
// it will output an array of DDL statements required to create
// the necessary elements to compose the table
// -------------------------------------------
// array(3) {
//  ['tables'] => array {
//      [0] => string(145) "CREATE TABLE users (
//          id INT64 NOT NULL,
//          name STRING(255) NOT NULL,
//          email STRING(255) NOT NULL,
//          password STRING(255) NOT NULL
//      ) PRIMARY KEY (id)"
//  }
//  ['indexes'] => array {
//      [0] => string(55) "CREATE UNIQUE INDEX users_email_unique ON users (email)"
//  }
//  ['constraints'] => array {}

The library outputs a multidimensional array with following keys 'tables', 'indexes', 'constraints' to insert on the Google Cloud Spanner engine.

Note: You may want to store the constraint keys to run at the end of all tables and indexes to prevent running a constraint for a table which is not created.

Returning DDL statements without semicolons

If for some reason you need each statement without semicolon at the end, you can use the method shouldAssignPrimaryKey:

$schemaParser = (new Parser())->shouldAssignSemicolon(false);

$ddl = $schemaParser->setTableName($tableName)
                  ->setDescribedTable($table)
                  ->setKeys($keys)
                  ->toDDL();

Dealing with schemas without Primary Keys

Since the primary key on cloud spanner is like almost required, by default if there's a table schema without PK it will generate a default column called by id which will be an int64 type. However you can modify the way this default column is created or disable it at all, for that check the following example:

use MgCosta\MysqlParser\Parser;
use MgCosta\MysqlParser\Dialect;
use MgCosta\MysqlParser\Exceptions\PrimaryKeyNotFoundException;

$schemaParser = new Parser();

$tableName = 'users';

$table = [
    [
        'Field' => 'name',
        'Type' => 'varchar(255)',
        'Null' => 'NO',
        'Key' => '',
        'Default' => null,
        'Extra' => ''
    ],
    [
        'Field' => 'email',
        'Type' => 'varchar(255)',
        'Null' => 'NO',
        'Key' => '',
        'Default' => null,
        'Extra' => ''
    ]
];

// define the default column id for a specific table
$ddl = $schemaParser->setDefaultID('column_id')
                  ->setTableName($tableName)
                  ->setDescribedTable($table)
                  ->setKeys($keys)
                  ->toDDL();

// disable the generation of default id
// it can lead on an exception

try {
    $schemaParser = (new Parser())->shouldAssignPrimaryKey(false);
    
    $ddl = $schemaParser->setTableName($tableName)
                    ->setDescribedTable($table)
                    ->setKeys($keys)
                    ->toDDL();

} catch(PrimaryKeyNotFoundException $e) {

}

Using the Dialect Service for MySQL

To help your life to fetch the data we need from MySQL to create the spanner statements, you can use the available service on your PDO or ORM / Query Builder:

This will simply generate a valid query string which you can use to fetch the columns & keys details.

The example below is Laravel based, but you can adapt it easily.

use Illuminate\Support\Facades\DB;
use MgCosta\MysqlParser\Parser;
use MgCosta\MysqlParser\Dialect;

$schemaParser = new Parser();
$mysqlDialect = new Dialect();

$databaseName = 'my_database';
$tableName = 'users';

// you can extract the table details doing the following
$table = DB::select(
    DB::raw($mysqlDialect->generateTableDetails($tableName))
);
$keys = DB::select(
    DB::raw($mysqlDialect->generateTableKeysDetails($databaseName, $tableName))
);

$ddl = $schemaParser->setTableName($tableName)
                    ->setDescribedTable($table)
                    ->setKeys($keys)
                    ->toDDL();

Prepare the data for migration

Sometimes you may have unexpected typed values to insert to Cloud Spanner, when you fetch the data from PHP PDOs system's, for that you can use the available transformer, which will prepare the data mapped with the described table.

For that follow the example below:

use MgCosta\MysqlParser\Transformer\SpannerTransformer;

$table = [
    [
        'Field' => 'name',
        'Type' => 'varchar(255)',
        'Null' => 'NO',
        'Key' => '',
        'Default' => null,
        'Extra' => ''
    ],
    [
        'Field' => 'value',
        'Type' => 'decimal(8,2)',
        'Null' => 'NO',
        'Key' => '',
        'Default' => null,
        'Extra' => ''
    ]
];

$rows = [
     [
        'name' => 'product',
        'value' => '50.20'
    ]
];

$transformer = (new SpannerTransformer())->setDescribedTable($table);
$results = $transformer->setRows($rows)->transform();

Roadmap

You can get more details of the plans for this early version on the following link.

Contributing

Please see CONTRIBUTING for details.

Credits

• [Miguel Costa][https://github.com/mgcostaParedes]
• [Mike Slowik][https://github.com/sl0wik]

License

The MIT License (MIT). Please see License File for more information.