چالش انتخاب دیتابیس
در طراحی و پیاده سازی یک سیستم نرم افزاری، اینکه از چه دیتابیسی برای نگه داری و ذخیره داده استفاده کنیم تصمیم مهمی است. هر دو دیتابیس MySQL و PostgreSQL در مرور زمان نشان داده اند که توانایی رقابت با دیتابیس های تجاری نظیر Oracle و SQL Server را دارند.
شهرت
MySql از جهت سرعت و راحتی در استفاده همیشه مشهور بوده و این درحالی است که PostgreSQL برای ارائه ابزار و امکانات پیشرفته تر شهرت خوبی دارد. اغلب PostgreSQL را نسخه متن باز Oracle توصیف میکنند.
مقایسه ویژگی ها
هردوی این دیتابیس ها امکان نصب روی سرور های ابری وان سنتر را دارند، جدول زیر برخی از ویژگی های دو پایگاه داده PostgreSQL و MySQL را باهم مقایسه می کند:
| PostgreSQL | MySQL | |
| Known as | The world’s most advanced open source database. | The world’s most popular open source database. |
| Development | PostgreSQL is an open source project. | MySQL is an open-source product. |
| Pronunciation | post gress queue ell | my ess queue ell |
| Licensing | MIT-style license | GNU General Public License |
| Implementation programming language | C | C/C++ |
| GUI tool | PgAdmin | MySQL Workbench |
| ACID | Yes | Yes |
| Storage engine | Single storage engine | Multiple storage engines e.g., InnoDB and MyISAM |
| Full-text search | Yes | Yes (Limited) |
| Drop a temporary table | No TEMP or TEMPORARY keyword in DROP TABLE statement | Support the TEMP or TEMPORARY keyword in the DROP TABLE statement that allows you to remove the temporary table only. |
| DROP TABLE | Support CASCADE option to drop table’s dependent objects e.g., tables and views. | Does not support CASCADE option. |
| TRUNCATE TABLE | PostgreSQL TRUNCATE TABLE supports more features like CASCADE, RESTART IDENTITY, CONTINUE IDENTITY, transaction-safe, etc. | MySQL TRUNCATE TABLE does not support CASCADE and transaction safe i.e,. once data is deleted, it cannot be rolled back. |
| Auto increment Column | SERIAL | AUTO_INCREMENT |
| Identity Column | Yes | No |
| Analytic functions | Yes | No |
| Data types | Support many advanced types such as array, hstore, and user-defined type. | SQL-standard types |
| Unsigned integer | No | Yes |
| Boolean type | Yes | Use TINYINT(1) internally for Boolean |
| IP address data type | Yes | No |
| Set default value for a column | Support both constant and function call | Must be a constant or CURRENT_TIMESTAMP for TIMESTAMP or DATETIME columns |
| CTE | Yes | Yes (Supported CTE since MySQL 8.0) |
| EXPLAIN output | More detailed | Less detailed |
| Materialized views | Yes | No |
| CHECK constraint | Yes | Yes (Supported since MySQL 8.0.16, Before that MySQL just ignored the CHECK constraint) |
| Table inheritance | Yes | No |
| Programming languages for stored procedures | Ruby, Perl, Python, TCL, PL/pgSQL, SQL, JavaScript, etc. | SQL:2003 syntax for stored procedures |
| FULL OUTER JOIN | Yes | No |
| INTERSECT | Yes | No |
| EXCEPT | Yes | No |
| Partial indexes | Yes | No |
| Bitmap indexes | Yes | No |
| Expression indexes | Yes | No |
| Covering indexes | Yes (since version 9.2) | Yes. MySQL supports covering indexes that allow data to be retrieved by scanning the index alone without touching the table data. This is advantageous in case of large tables with millions of rows. |
| Triggers | Support triggers that can fire on most types of command, except for ones affecting the database globally e.g., roles and tablespaces. | Limited to some commands |
| Partitioning | RANGE, LIST | RANGE, LIST, HASH, KEY, and composite partitioning using a combination of RANGE or LIST with HASH or KEY subpartitions |
| Task Schedule | pgAgent | Scheduled event |
| Connection Scalability | Each new connection is an OS process | Each new connection is an OS thread |
