# Abstract Class yii\db\Schema

Inheritance | yii\db\Schema » yii\base\BaseObject
Implements | yii\base\Configurable
Subclasses | yii\db\cubrid\Schema, yii\db\mssql\Schema, yii\db\mysql\Schema, yii\db\oci\Schema, yii\db\pgsql\Schema, yii\db\sqlite\Schema
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/db/Schema.php

Schema is the base class for concrete DBMS-specific schema classes.

Schema represents the database schema information that is DBMS specific.

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$columnSchemaClass | string|array | Column schema class or class config | yii\db\Schema
$db | yii\db\Connection | The database connection | yii\db\Schema
$defaultSchema | string | The default schema name used for the current session. | yii\db\Schema
$exceptionMap | array | Map of DB errors and corresponding exceptions If left part is found in DB error message exception class from the right part is used. | yii\db\Schema
$lastInsertID | string | The row ID of the last row inserted, or the last value retrieved from the sequence object. This property is read-only. | yii\db\Schema
$queryBuilder | yii\db\QueryBuilder | The query builder for this connection. This property is read-only. | yii\db\Schema
$schemaNames | string[] | All schema names in the database, except system schemas. This property is read-only. | yii\db\Schema
$serverVersion | string | Server version as a string. This property is read-only. | yii\db\Schema
$tableNames | string[] | All table names in the database. This property is read-only. | yii\db\Schema
$tableSchemas | yii\db\TableSchema[] | The metadata for all tables in the database. Each array element is an instance of yii\db\TableSchema or its child class. This property is read-only. | yii\db\Schema

$transactionIsolationLevel

string

The transaction isolation level to use for this transaction. This can be one of yii\db\Transaction::READ_UNCOMMITTED, yii\db\Transaction::READ_COMMITTED, yii\db\Transaction::REPEATABLE_READ and yii\db\Transaction::SERIALIZABLE but also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. This property is write-only.

yii\db\Schema

## Protected Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$columnQuoteCharacter | string|string[] | Character used to quote column names. | yii\db\Schema
$tableQuoteCharacter | string|string[] | Character used to quote schema, table, etc. | yii\db\Schema

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\BaseObject
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of an object property. | yii\base\BaseObject
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\BaseObject
__set() | Sets value of an object property. | yii\base\BaseObject
__unset() | Sets an object property to null. | yii\base\BaseObject
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\BaseObject
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\BaseObject
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
convertException() | Converts a DB exception to a more concrete one if possible. | yii\db\Schema
createColumnSchemaBuilder() | Create a column schema builder instance giving the type and value precision. | yii\db\Schema
createQueryBuilder() | Creates a query builder for the database. | yii\db\Schema
createSavepoint() | Creates a new savepoint. | yii\db\Schema
findUniqueIndexes() | Returns all unique indexes for the given table. | yii\db\Schema
getLastInsertID() | Returns the ID of the last inserted row or sequence value. | yii\db\Schema
getPdoType() | Determines the PDO type for the given PHP data value. | yii\db\Schema
getQueryBuilder() |  | yii\db\Schema
getRawTableName() | Returns the actual name of a given table name. | yii\db\Schema
getSchemaNames() | Returns all schema names in the database, except system schemas. | yii\db\Schema
getServerVersion() | Returns a server version as a string comparable by \version_compare(). | yii\db\Schema
getTableNames() | Returns all table names in the database. | yii\db\Schema
getTableSchema() | Obtains the metadata for the named table. | yii\db\Schema
getTableSchemas() | Returns the metadata for all tables in the database. | yii\db\Schema
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\BaseObject
hasProperty() | Returns a value indicating whether a property is defined. | yii\base\BaseObject
init() | Initializes the object. | yii\base\BaseObject
insert() | Executes the INSERT command, returning primary key values. | yii\db\Schema
isReadQuery() | Returns a value indicating whether a SQL statement is for read purpose. | yii\db\Schema
quoteColumnName() | Quotes a column name for use in a query. | yii\db\Schema
quoteSimpleColumnName() | Quotes a simple column name for use in a query. | yii\db\Schema
quoteSimpleTableName() | Quotes a simple table name for use in a query. | yii\db\Schema
quoteTableName() | Quotes a table name for use in a query. | yii\db\Schema
quoteValue() | Quotes a string value for use in a query. | yii\db\Schema
refresh() | Refreshes the schema. | yii\db\Schema
refreshTableSchema() | Refreshes the particular table schema. | yii\db\Schema
releaseSavepoint() | Releases an existing savepoint. | yii\db\Schema
rollBackSavepoint() | Rolls back to a previously created savepoint. | yii\db\Schema
setTransactionIsolationLevel() | Sets the isolation level of the current transaction. | yii\db\Schema
supportsSavepoint() |  | yii\db\Schema
unquoteSimpleColumnName() | Unquotes a simple column name. | yii\db\Schema
unquoteSimpleTableName() | Unquotes a simple table name. | yii\db\Schema

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
createColumnSchema() | Creates a column schema for the database. | yii\db\Schema
findSchemaNames() | Returns all schema names in the database, including the default one but not system schemas. | yii\db\Schema
findTableNames() | Returns all table names in the database. | yii\db\Schema
getCacheKey() | Returns the cache key for the specified table name. | yii\db\Schema
getCacheTag() | Returns the cache tag name. | yii\db\Schema
getColumnPhpType() | Extracts the PHP type from abstract DB type. | yii\db\Schema
getSchemaMetadata() | Returns the metadata of the given type for all tables in the given schema. | yii\db\Schema
getTableMetadata() | Returns the metadata of the given type for the given table. | yii\db\Schema
getTableNameParts() | Splits full table name into parts | yii\db\Schema
loadTableSchema() | Loads the metadata for the specified table. | yii\db\Schema
normalizePdoRowKeyCase() | Changes row's array key case to lower if PDO's one is set to uppercase. | yii\db\Schema
resolveTableName() | Resolves the table name and schema name (if any). | yii\db\Schema
setTableMetadata() | Sets the metadata of the given type for the given table. | yii\db\Schema

## Constants

Hide inherited constants

Constant | Value | Description | Defined By
--- | --- | --- | ---
SCHEMA_CACHE_VERSION | 1 | Schema cache version, to detect incompatibilities in cached values when the data format of the cache changes. | yii\db\Schema
TYPE_BIGINT | 'bigint' |  | yii\db\Schema
TYPE_BIGPK | 'bigpk' |  | yii\db\Schema
TYPE_BINARY | 'binary' |  | yii\db\Schema
TYPE_BOOLEAN | 'boolean' |  | yii\db\Schema
TYPE_CHAR | 'char' |  | yii\db\Schema
TYPE_DATE | 'date' |  | yii\db\Schema
TYPE_DATETIME | 'datetime' |  | yii\db\Schema
TYPE_DECIMAL | 'decimal' |  | yii\db\Schema
TYPE_DOUBLE | 'double' |  | yii\db\Schema
TYPE_FLOAT | 'float' |  | yii\db\Schema
TYPE_INTEGER | 'integer' |  | yii\db\Schema
TYPE_JSON | 'json' |  | yii\db\Schema
TYPE_MONEY | 'money' |  | yii\db\Schema
TYPE_PK | 'pk' |  | yii\db\Schema
TYPE_SMALLINT | 'smallint' |  | yii\db\Schema
TYPE_STRING | 'string' |  | yii\db\Schema
TYPE_TEXT | 'text' |  | yii\db\Schema
TYPE_TIME | 'time' |  | yii\db\Schema
TYPE_TIMESTAMP | 'timestamp' |  | yii\db\Schema
TYPE_TINYINT | 'tinyint' |  | yii\db\Schema
TYPE_UBIGPK | 'ubigpk' |  | yii\db\Schema
TYPE_UPK | 'upk' |  | yii\db\Schema

## Property Details

$columnQuoteCharacter protected property (available since version 2.0.14)

Character used to quote column names. An array of 2 characters can be used in case starting and ending characters are different.

protected string|string[] $columnQuoteCharacter = '"'
$columnSchemaClass public property (available since version 2.0.11)

Column schema class or class config

public string|array $columnSchemaClass = 'yii\db\ColumnSchema'
$db public property

The database connection

public yii\db\Connection $db = null
$defaultSchema public property

The default schema name used for the current session.

public string $defaultSchema = null
$exceptionMap public property

Map of DB errors and corresponding exceptions If left part is found in DB error message exception class from the right part is used.

public array $exceptionMap = ['SQLSTATE[23' => 'yii\db\IntegrityException']
$lastInsertID public property

The row ID of the last row inserted, or the last value retrieved from the sequence object. This property is read-only.

public string $lastInsertID = null
$queryBuilder public property

The query builder for this connection. This property is read-only.

public yii\db\QueryBuilder $queryBuilder = null
$schemaNames public property

All schema names in the database, except system schemas. This property is read-only.

public string[] $schemaNames = null
$serverVersion public property

Server version as a string. This property is read-only.

public string $serverVersion = null
$tableNames public property

All table names in the database. This property is read-only.

public string[] $tableNames = null
$tableQuoteCharacter protected property (available since version 2.0.14)

Character used to quote schema, table, etc. names. An array of 2 characters can be used in case starting and ending characters are different.

protected string|string[] $tableQuoteCharacter = "'"
$tableSchemas public property

The metadata for all tables in the database. Each array element is an instance of yii\db\TableSchema or its child class. This property is read-only.

public yii\db\TableSchema[] $tableSchemas = null
$transactionIsolationLevel public property

The transaction isolation level to use for this transaction. This can be one of yii\db\Transaction::READ_UNCOMMITTED, yii\db\Transaction::READ_COMMITTED, yii\db\Transaction::REPEATABLE_READ and yii\db\Transaction::SERIALIZABLE but also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. This property is write-only.

public string $transactionIsolationLevel = null

## Method Details

convertException() public method

Converts a DB exception to a more concrete one if possible.

public yii\db\Exception convertException ( Exception $e, $rawSql )
$e | Exception |
$rawSql | string | SQL that produced exception

createColumnSchema() protected method

Creates a column schema for the database.

This method may be overridden by child classes to create a DBMS-specific column schema.

protected yii\db\ColumnSchema createColumnSchema ( )
return | yii\db\ColumnSchema | Column schema instance.
throws | yii\base\InvalidConfigException | if a column schema class cannot be created.

createColumnSchemaBuilder() public method (available since version 2.0.6)

Create a column schema builder instance giving the type and value precision.

This method may be overridden by child classes to create a DBMS-specific column schema builder.

public yii\db\ColumnSchemaBuilder createColumnSchemaBuilder ( $type, $length = null )
$type | string | Type of the column. See yii\db\ColumnSchemaBuilder::$type.
$length | integer|string|array | Length or precision of the column. See yii\db\ColumnSchemaBuilder::$length.
return | yii\db\ColumnSchemaBuilder | Column schema builder instance

createQueryBuilder() public method

Creates a query builder for the database.

This method may be overridden by child classes to create a DBMS-specific query builder.

public yii\db\QueryBuilder createQueryBuilder ( )
return | yii\db\QueryBuilder | Query builder instance

createSavepoint() public method

Creates a new savepoint.

public void createSavepoint ( $name )
$name | string | The savepoint name

findSchemaNames() protected method (available since version 2.0.4)

Returns all schema names in the database, including the default one but not system schemas.

This method should be overridden by child classes in order to support this feature because the default implementation simply throws an exception.

protected array findSchemaNames ( )
return | array | All schema names in the database, except system schemas.
throws | yii\base\NotSupportedException | if this method is not supported by the DBMS.

findTableNames() protected method

Returns all table names in the database.

This method should be overridden by child classes in order to support this feature because the default implementation simply throws an exception.

protected array findTableNames ( $schema = '' )
$schema | string | The schema of the tables. Defaults to empty string, meaning the current or default schema.
return | array | All table names in the database. The names have NO schema name prefix.
throws | yii\base\NotSupportedException | if this method is not supported by the DBMS.

findUniqueIndexes() public method

Returns all unique indexes for the given table.

Each array element is of the following structure:

    [
     'IndexName1' => ['col1' [, ...]],
     'IndexName2' => ['col2' [, ...]],
    ]

This method should be overridden by child classes in order to support this feature because the default implementation simply throws an exception

public array findUniqueIndexes ( $table )
$table | yii\db\TableSchema | The table metadata
return | array | All unique indexes for the given table.
throws | yii\base\NotSupportedException | if this method is called

getCacheKey() protected method

Returns the cache key for the specified table name.

protected mixed getCacheKey ( $name )
$name | string | The table name.
return | mixed | The cache key.

getCacheTag() protected method

Returns the cache tag name.

This allows refresh() to invalidate all cached table schemas.

protected string getCacheTag ( )
return | string | The cache tag name

getColumnPhpType() protected method

Extracts the PHP type from abstract DB type.

protected string getColumnPhpType ( $column )
$column | yii\db\ColumnSchema | The column schema information
return | string | PHP type name

getLastInsertID() public method

Returns the ID of the last inserted row or sequence value.

See also https://secure.php.net/manual/en/function.PDO-lastInsertId.php.

public string getLastInsertID ( $sequenceName = '' )
$sequenceName | string | Name of the sequence object (required by some DBMS)
return | string | The row ID of the last row inserted, or the last value retrieved from the sequence object
throws | yii\base\InvalidCallException | if the DB connection is not active

getPdoType() public method

Determines the PDO type for the given PHP data value.

See also https://secure.php.net/manual/en/pdo.constants.php.

public integer getPdoType ( $data )
$data | mixed | The data whose PDO type is to be determined
return | integer | The PDO type

getQueryBuilder() public method

public yii\db\QueryBuilder getQueryBuilder ( )
return | yii\db\QueryBuilder | The query builder for this connection.

getRawTableName() public method

Returns the actual name of a given table name.

This method will strip off curly brackets from the given table name and replace the percentage character '%' with yii\db\Connection::$tablePrefix.

public string getRawTableName ( $name )
$name | string | The table name to be converted
return | string | The real name of the given table name

getSchemaMetadata() protected method (available since version 2.0.13)

Returns the metadata of the given type for all tables in the given schema.

This method will call a `'getTable' . ucfirst($type)` named method with the table name and the refresh flag to obtain the metadata.

protected array getSchemaMetadata ( $schema, $type, $refresh )
$schema | string | The schema of the metadata. Defaults to empty string, meaning the current or default schema name.
$type | string | Metadata type.
$refresh | boolean | Whether to fetch the latest available table metadata. If this is `false`, cached data may be returned if available.
return | array | Array of metadata.

getSchemaNames() public method (available since version 2.0.4)

Returns all schema names in the database, except system schemas.

public string[] getSchemaNames ( $refresh = false )
$refresh | boolean | Whether to fetch the latest available schema names. If this is false, schema names fetched previously (if available) will be returned.
return | string[] | All schema names in the database, except system schemas.

getServerVersion() public method (available since version 2.0.14)

Returns a server version as a string comparable by \version_compare().

public string getServerVersion ( )
return | string | Server version as a string.

getTableMetadata() protected method (available since version 2.0.13)

Returns the metadata of the given type for the given table.

If there's no metadata in the cache, this method will call a `'loadTable' . ucfirst($type)` named method with the table name to obtain the metadata.

protected mixed getTableMetadata ( $name, $type, $refresh )
$name | string | Table name. The table name may contain schema name if any. Do not quote the table name.
$type | string | Metadata type.
$refresh | boolean | Whether to reload the table metadata even if it is found in the cache.
return | mixed | Metadata.

getTableNameParts() protected method (available since version 2.0.22)

Splits full table name into parts

protected array getTableNameParts ( $name )
$name | string |

getTableNames() public method

Returns all table names in the database.

public string[] getTableNames ( $schema = '', $refresh = false )
$schema | string | The schema of the tables. Defaults to empty string, meaning the current or default schema name. If not empty, the returned table names will be prefixed with the schema name.
$refresh | boolean | Whether to fetch the latest available table names. If this is false, table names fetched previously (if available) will be returned.
return | string[] | All table names in the database.

getTableSchema() public method

Obtains the metadata for the named table.

public yii\db\TableSchema|null getTableSchema ( $name, $refresh = false )
$name | string | Table name. The table name may contain schema name if any. Do not quote the table name.
$refresh | boolean | Whether to reload the table schema even if it is found in the cache.
return | yii\db\TableSchema|null | Table metadata. `null` if the named table does not exist.

getTableSchemas() public method

Returns the metadata for all tables in the database.

public yii\db\TableSchema[] getTableSchemas ( $schema = '', $refresh = false )
$schema | string | The schema of the tables. Defaults to empty string, meaning the current or default schema name.
$refresh | boolean | Whether to fetch the latest available table schemas. If this is `false`, cached data may be returned if available.
return | yii\db\TableSchema[] | The metadata for all tables in the database. Each array element is an instance of yii\db\TableSchema or its child class.

insert() public method (available since version 2.0.4)

Executes the INSERT command, returning primary key values.

public array|false insert ( $table, $columns )
$table | string | The table that new rows will be inserted into.
$columns | array | The column data (name => value) to be inserted into the table.
return | array|false | Primary key values or false if the command fails

isReadQuery() public method

Returns a value indicating whether a SQL statement is for read purpose.

public boolean isReadQuery ( $sql )
$sql | string | The SQL statement
return | boolean | Whether a SQL statement is for read purpose.

loadTableSchema() protected abstract method

Loads the metadata for the specified table.

protected abstract yii\db\TableSchema|null loadTableSchema ( $name )
$name | string | Table name
return | yii\db\TableSchema|null | DBMS-dependent table metadata, `null` if the table does not exist.

normalizePdoRowKeyCase() protected method (available since version 2.0.13)

Changes row's array key case to lower if PDO's one is set to uppercase.

protected array normalizePdoRowKeyCase ( array $row, $multiple )
$row | array | Row's array or an array of row's arrays.
$multiple | boolean | Whether multiple rows or a single row passed.
return | array | Normalized row or rows.

quoteColumnName() public method

Quotes a column name for use in a query.

If the column name contains prefix, the prefix will also be properly quoted. If the column name is already quoted or contains '(', '[[' or '{{', then this method will do nothing.

See also quoteSimpleColumnName().

public string quoteColumnName ( $name )
$name | string | Column name
return | string | The properly quoted column name

quoteSimpleColumnName() public method

Quotes a simple column name for use in a query.

A simple column name should contain the column name only without any prefix. If the column name is already quoted or is the asterisk character '*', this method will do nothing.

public string quoteSimpleColumnName ( $name )
$name | string | Column name
return | string | The properly quoted column name

quoteSimpleTableName() public method

Quotes a simple table name for use in a query.

A simple table name should contain the table name only without any schema prefix. If the table name is already quoted, this method will do nothing.

public string quoteSimpleTableName ( $name )
$name | string | Table name
return | string | The properly quoted table name

quoteTableName() public method

Quotes a table name for use in a query.

If the table name contains schema prefix, the prefix will also be properly quoted. If the table name is already quoted or contains '(' or '{{', then this method will do nothing.

See also quoteSimpleTableName().

public string quoteTableName ( $name )
$name | string | Table name
return | string | The properly quoted table name

quoteValue() public method

Quotes a string value for use in a query.

Note that if the parameter is not a string, it will be returned without change.

See also https://secure.php.net/manual/en/function.PDO-quote.php.

public string quoteValue ( $str )
$str | string | String to be quoted
return | string | The properly quoted string

refresh() public method

Refreshes the schema.

This method cleans up all cached table schemas so that they can be re-created later to reflect the database schema change.

public void refresh ( )

refreshTableSchema() public method (available since version 2.0.6)

Refreshes the particular table schema.

This method cleans up cached table schema so that it can be re-created later to reflect the database schema change.

public void refreshTableSchema ( $name )
$name | string | Table name.

releaseSavepoint() public method

Releases an existing savepoint.

public void releaseSavepoint ( $name )
$name | string | The savepoint name

resolveTableName() protected method (available since version 2.0.13)

Resolves the table name and schema name (if any).

protected yii\db\TableSchema resolveTableName ( $name )
$name | string | The table name
return | yii\db\TableSchema | yii\db\TableSchema with resolved table, schema, etc. names.
throws | yii\base\NotSupportedException | if this method is not supported by the DBMS.

rollBackSavepoint() public method

Rolls back to a previously created savepoint.

public void rollBackSavepoint ( $name )
$name | string | The savepoint name

setTableMetadata() protected method (available since version 2.0.13)

Sets the metadata of the given type for the given table.

protected void setTableMetadata ( $name, $type, $data )
$name | string | Table name.
$type | string | Metadata type.
$data | mixed | Metadata.

setTransactionIsolationLevel() public method

Sets the isolation level of the current transaction.

See also http://en.wikipedia.org/wiki/Isolation_(database_systems)#Isolation_levels.

public void setTransactionIsolationLevel ( $level )
$level | string | The transaction isolation level to use for this transaction. This can be one of yii\db\Transaction::READ_UNCOMMITTED, yii\db\Transaction::READ_COMMITTED, yii\db\Transaction::REPEATABLE_READ and yii\db\Transaction::SERIALIZABLE but also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`.

supportsSavepoint() public method

public boolean supportsSavepoint ( )
return | boolean | Whether this DBMS supports savepoint.

unquoteSimpleColumnName() public method (available since version 2.0.14)

Unquotes a simple column name.

A simple column name should contain the column name only without any prefix. If the column name is not quoted or is the asterisk character '*', this method will do nothing.

public string unquoteSimpleColumnName ( $name )
$name | string | Column name.
return | string | Unquoted column name.

unquoteSimpleTableName() public method (available since version 2.0.14)

Unquotes a simple table name.

A simple table name should contain the table name only without any schema prefix. If the table name is not quoted, this method will do nothing.

public string unquoteSimpleTableName ( $name )
$name | string | Table name.
return | string | Unquoted table name.