Package org.apache.flink.table.legacy.api

Class TableSchema.Builder

java.lang.Object

org.apache.flink.table.legacy.api.TableSchema.Builder

Enclosing class:

TableSchema

@Internal
public static class TableSchema.Builder
extends Object

Builder for creating a TableSchema.

Constructor Summary

Constructors

Constructor	Description
Builder()

Method Summary

Modifier and Type	Method	Description
TableSchema.Builder	add(TableColumn column)	Adds a TableColumn to this builder.
TableSchema	build()	Returns a TableSchema instance.
TableSchema.Builder	field(String name, TypeInformation<?> typeInfo)	Deprecated. This method will be removed in future versions as it uses the old type system.
TableSchema.Builder	field(String name, DataType dataType)	Add a field with name and data type.
TableSchema.Builder	field(String name, DataType dataType, String expression)	Add a computed field which is generated by the given expression.
TableSchema.Builder	fields(String[] names, DataType[] dataTypes)	Add an array of fields with names and data types.
TableSchema.Builder	primaryKey(String... columns)	Creates a primary key constraint for a set of given columns.
TableSchema.Builder	primaryKey(String name, String[] columns)	Creates a primary key constraint for a set of given columns.
TableSchema.Builder	watermark(String rowtimeAttribute, String watermarkExpressionString, DataType watermarkExprOutputType)	Specifies the previously defined field as an event-time attribute and specifies the watermark strategy.
TableSchema.Builder	watermark(WatermarkSpec watermarkSpec)	Adds the given WatermarkSpec to this builder.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Builder

public Builder()

Method Detail

field

public TableSchema.Builder field(String name,
                                 DataType dataType)

Add a field with name and data type.

The call order of this method determines the order of fields in the schema.

field

public TableSchema.Builder field(String name,
                                 DataType dataType,
                                 String expression)

Add a computed field which is generated by the given expression. This also defines the field name and the data type.

The call order of this method determines the order of fields in the schema.

The returned expression should be a SQL-style expression whose identifiers should be all quoted and expanded.

It should be expanded because this expression may be persisted then deserialized from the catalog, an expanded identifier would avoid the ambiguity if there are same name UDF referenced from different paths. For example, if there is a UDF named "my_udf" from path "my_catalog.my_database", you could pass in an expression like "`my_catalog`.`my_database`.`my_udf`(`f0`) + 1";

It should be quoted because user could use a reserved keyword as the identifier, and we have no idea if it is quoted when deserialize from the catalog, so we force to use quoted identifier here. But framework will not check whether it is qualified and quoted or not.

Parameters:

name - Field name

dataType - Field data type

expression - Computed column expression.

add

public TableSchema.Builder add(TableColumn column)

Adds a TableColumn to this builder.

The call order of this method determines the order of fields in the schema.

fields

public TableSchema.Builder fields(String[] names,
                                  DataType[] dataTypes)

Add an array of fields with names and data types.

The call order of this method determines the order of fields in the schema.

field

@Deprecated
public TableSchema.Builder field(String name,
                                 TypeInformation<?> typeInfo)

Deprecated.

This method will be removed in future versions as it uses the old type system. It is recommended to use field(String, DataType) instead which uses the new type system based on DataTypes. Please make sure to use either the old or the new type system consistently to avoid unintended behavior. See the website documentation for more information.

watermark

public TableSchema.Builder watermark(String rowtimeAttribute,
                                     String watermarkExpressionString,
                                     DataType watermarkExprOutputType)

Specifies the previously defined field as an event-time attribute and specifies the watermark strategy.

Parameters:

rowtimeAttribute - the field name as a rowtime attribute, can be a nested field using dot separator.

watermarkExpressionString - the string representation of watermark generation expression, e.g. "ts - INTERVAL '5' SECOND". The string is a qualified SQL expression string (UDFs are expanded) but will not be validated by TableSchema.

watermarkExprOutputType - the data type of the computation result of watermark generation expression. Whether the data type equals to the output type of expression will also not be validated by TableSchema.

watermark

public TableSchema.Builder watermark(WatermarkSpec watermarkSpec)

Adds the given WatermarkSpec to this builder.

primaryKey

public TableSchema.Builder primaryKey(String... columns)

Creates a primary key constraint for a set of given columns. The primary key is informational only. It will not be enforced. It can be used for optimizations. It is the owner's of the data responsibility to ensure uniqueness of the data.

The primary key will be assigned a random name.

Parameters:

columns - array of columns that form a unique primary key

primaryKey

public TableSchema.Builder primaryKey(String name,
                                      String[] columns)

Creates a primary key constraint for a set of given columns. The primary key is informational only. It will not be enforced. It can be used for optimizations. It is the owner's of the data responsibility to ensure

Parameters:

columns - array of columns that form a unique primary key

name - name for the primary key, can be used to reference the constraint

build

public TableSchema build()

Returns a TableSchema instance.