Contents
What is information schema table?
INFORMATION_SCHEMA provides access to database metadata, information about the MySQL server such as the name of a database or table, the data type of a column, or access privileges. Other terms that are sometimes used for this information are data dictionary and system catalog.
What is MySQL InnoDB table?
InnoDB is a storage engine for the database management system MySQL and MariaDB. Since the release of MySQL 5.5. 5 in 2010, it replaced MyISAM as MySQL’s default table type. It provides the standard ACID-compliant transaction features, along with foreign key support (Declarative Referential Integrity).
What is MySQL table schema?
The mysql schema is the system schema. It contains tables that store information required by the MySQL server as it runs. A broad categorization is that the mysql schema contains data dictionary tables that store database object metadata, and system tables used for other operational purposes.
What means InnoDB?
InnoDB is a general-purpose storage engine that balances high reliability and high performance. In MySQL 5.6, InnoDB is the default MySQL storage engine. Unless you have configured a different default storage engine, issuing a CREATE TABLE statement without an ENGINE clause creates an InnoDB table.
Is a schema a database?
A schema is a collection of database objects. A schema is owned by a database user and has the same name as that user.
How do I get a list of tables in a schema?
SELECT table_name, table_schema, table_type FROM information_schema. tables ORDER BY table_name ASC; This will show the name of the table, which schema it belongs to, and the type. The type will either be “BASE TABLE” for tables or “VIEW” for views.
Where does schema information come from in InnoDB?
You can extract metadata about schema objects managed by InnoDB using InnoDB INFORMATION_SCHEMA system tables. This information comes from the InnoDB internal system tables (also referred to as the InnoDB data dictionary), which cannot be queried directly like regular InnoDB tables.
What does InnoDB _ SYS _ columns do in MySQL?
INNODB_SYS_TABLES provides metadata about InnoDB tables, equivalent to the information in the SYS_TABLES table in the InnoDB data dictionary. INNODB_SYS_COLUMNS provides metadata about InnoDB table columns, equivalent to the information in the SYS_COLUMNS table in the InnoDB data dictionary.
What’s the difference between count and information in InnoDB?
For InnoDB tables it depends on the size of the table as the engine has to do either scan the whole table or a whole index to get the accurate count. The bigger the table, the slower it gets.
Which is the schema table interface in MySQL?
The InnoDB INFORMATION_SCHEMA table interface allows you to query this data using SQL.