Class

org.apache.spark.sql

DataFrameWriter

Related Doc: package sql

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final class DataFrameWriter[T] extends AnyRef

Interface used to write a Dataset to external storage systems (e.g. file systems, key-value stores, etc). Use Dataset.write to access this.

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@Stable()
Since

1.4.0

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  1. final def !=(arg0: Any): Boolean

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  2. final def ##(): Int

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  3. final def ==(arg0: Any): Boolean

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  4. final def asInstanceOf[T0]: T0

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  5. def bucketBy(numBuckets: Int, colName: String, colNames: String*): DataFrameWriter[T]

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    Buckets the output by the given columns.

    Buckets the output by the given columns. If specified, the output is laid out on the file system similar to Hive's bucketing scheme.

    This is applicable for all file-based data sources (e.g. Parquet, JSON) staring Spark 2.1.0.

    Annotations
    @varargs()
    Since

    2.0

  6. def clone(): AnyRef

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    protected[java.lang]
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    @throws( ... )
  7. def csv(path: String): Unit

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    Saves the content of the DataFrame in CSV format at the specified path.

    Saves the content of the DataFrame in CSV format at the specified path. This is equivalent to:

    format("csv").save(path)

    You can set the following CSV-specific option(s) for writing CSV files:

    • sep (default ,): sets the single character as a separator for each field and value.
    • quote (default "): sets the single character used for escaping quoted values where the separator can be part of the value. If an empty string is set, it uses u0000 (null character).
    • escape (default \): sets the single character used for escaping quotes inside an already quoted value.
    • escapeQuotes (default true): a flag indicating whether values containing quotes should always be enclosed in quotes. Default is to escape all values containing a quote character.
    • quoteAll (default false): a flag indicating whether all values should always be enclosed in quotes. Default is to only escape values containing a quote character.
    • header (default false): writes the names of columns as the first line.
    • nullValue (default empty string): sets the string representation of a null value.
    • compression (default null): compression codec to use when saving to file. This can be one of the known case-insensitive shorten names (none, bzip2, gzip, lz4, snappy and deflate).
    • dateFormat (default yyyy-MM-dd): sets the string that indicates a date format. Custom date formats follow the formats at java.text.SimpleDateFormat. This applies to date type.
    • timestampFormat (default yyyy-MM-dd'T'HH:mm:ss.SSSXXX): sets the string that indicates a timestamp format. Custom date formats follow the formats at java.text.SimpleDateFormat. This applies to timestamp type.
    • ignoreLeadingWhiteSpace (default true): a flag indicating whether or not leading whitespaces from values being written should be skipped.
    • ignoreTrailingWhiteSpace (default true): a flag indicating defines whether or not trailing whitespaces from values being written should be skipped.
    Since

    2.0.0

  8. final def eq(arg0: AnyRef): Boolean

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  9. def equals(arg0: Any): Boolean

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  10. def finalize(): Unit

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  11. def format(source: String): DataFrameWriter[T]

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    Specifies the underlying output data source.

    Specifies the underlying output data source. Built-in options include "parquet", "json", etc.

    Since

    1.4.0

  12. final def getClass(): Class[_]

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  13. def hashCode(): Int

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  14. def insertInto(tableName: String): Unit

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    Inserts the content of the DataFrame to the specified table.

    Inserts the content of the DataFrame to the specified table. It requires that the schema of the DataFrame is the same as the schema of the table.

    Since

    1.4.0

    Note

    Unlike saveAsTable, insertInto ignores the column names and just uses position-based resolution. For example:

    scala> Seq((1, 2)).toDF("i", "j").write.mode("overwrite").saveAsTable("t1")
    scala> Seq((3, 4)).toDF("j", "i").write.insertInto("t1")
    scala> Seq((5, 6)).toDF("a", "b").write.insertInto("t1")
    scala> sql("select * from t1").show
    +---+---+
    |  i|  j|
    +---+---+
    |  5|  6|
    |  3|  4|
    |  1|  2|
    +---+---+

    Because it inserts data to an existing table, format or options will be ignored.

  15. final def isInstanceOf[T0]: Boolean

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  16. def jdbc(url: String, table: String, connectionProperties: Properties): Unit

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    Saves the content of the DataFrame to an external database table via JDBC.

    Saves the content of the DataFrame to an external database table via JDBC. In the case the table already exists in the external database, behavior of this function depends on the save mode, specified by the mode function (default to throwing an exception).

    Don't create too many partitions in parallel on a large cluster; otherwise Spark might crash your external database systems.

    You can set the following JDBC-specific option(s) for storing JDBC:

    • truncate (default false): use TRUNCATE TABLE instead of DROP TABLE.

    In case of failures, users should turn off truncate option to use DROP TABLE again. Also, due to the different behavior of TRUNCATE TABLE among DBMS, it's not always safe to use this. MySQLDialect, DB2Dialect, MsSqlServerDialect, DerbyDialect, and OracleDialect supports this while PostgresDialect and default JDBCDirect doesn't. For unknown and unsupported JDBCDirect, the user option truncate is ignored.

    url

    JDBC database url of the form jdbc:subprotocol:subname

    table

    Name of the table in the external database.

    connectionProperties

    JDBC database connection arguments, a list of arbitrary string tag/value. Normally at least a "user" and "password" property should be included. "batchsize" can be used to control the number of rows per insert. "isolationLevel" can be one of "NONE", "READ_COMMITTED", "READ_UNCOMMITTED", "REPEATABLE_READ", or "SERIALIZABLE", corresponding to standard transaction isolation levels defined by JDBC's Connection object, with default of "READ_UNCOMMITTED".

    Since

    1.4.0

  17. def json(path: String): Unit

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    Saves the content of the DataFrame in JSON format ( JSON Lines text format or newline-delimited JSON) at the specified path.

    Saves the content of the DataFrame in JSON format ( JSON Lines text format or newline-delimited JSON) at the specified path. This is equivalent to:

    format("json").save(path)

    You can set the following JSON-specific option(s) for writing JSON files:

    • compression (default null): compression codec to use when saving to file. This can be one of the known case-insensitive shorten names (none, bzip2, gzip, lz4, snappy and deflate).
    • dateFormat (default yyyy-MM-dd): sets the string that indicates a date format. Custom date formats follow the formats at java.text.SimpleDateFormat. This applies to date type.
    • timestampFormat (default yyyy-MM-dd'T'HH:mm:ss.SSSXXX): sets the string that indicates a timestamp format. Custom date formats follow the formats at java.text.SimpleDateFormat. This applies to timestamp type.
    Since

    1.4.0

  18. def mode(saveMode: String): DataFrameWriter[T]

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    Specifies the behavior when data or table already exists.

    Specifies the behavior when data or table already exists. Options include:

    • overwrite: overwrite the existing data.
    • append: append the data.
    • ignore: ignore the operation (i.e. no-op).
    • error or errorifexists: default option, throw an exception at runtime.
    Since

    1.4.0

  19. def mode(saveMode: SaveMode): DataFrameWriter[T]

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    Specifies the behavior when data or table already exists.

    Specifies the behavior when data or table already exists. Options include:

    • SaveMode.Overwrite: overwrite the existing data.
    • SaveMode.Append: append the data.
    • SaveMode.Ignore: ignore the operation (i.e. no-op).
    • SaveMode.ErrorIfExists: default option, throw an exception at runtime.
    Since

    1.4.0

  20. final def ne(arg0: AnyRef): Boolean

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  21. final def notify(): Unit

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  22. final def notifyAll(): Unit

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  23. def option(key: String, value: Double): DataFrameWriter[T]

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    Adds an output option for the underlying data source.

    Adds an output option for the underlying data source.

    Since

    2.0.0

  24. def option(key: String, value: Long): DataFrameWriter[T]

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    Adds an output option for the underlying data source.

    Adds an output option for the underlying data source.

    Since

    2.0.0

  25. def option(key: String, value: Boolean): DataFrameWriter[T]

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    Adds an output option for the underlying data source.

    Adds an output option for the underlying data source.

    Since

    2.0.0

  26. def option(key: String, value: String): DataFrameWriter[T]

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    Adds an output option for the underlying data source.

    Adds an output option for the underlying data source.

    You can set the following option(s):

    • timeZone (default session local timezone): sets the string that indicates a timezone to be used to format timestamps in the JSON/CSV datasources or partition values.
    Since

    1.4.0

  27. def options(options: Map[String, String]): DataFrameWriter[T]

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    Adds output options for the underlying data source.

    Adds output options for the underlying data source.

    You can set the following option(s):

    • timeZone (default session local timezone): sets the string that indicates a timezone to be used to format timestamps in the JSON/CSV datasources or partition values.
    Since

    1.4.0

  28. def options(options: Map[String, String]): DataFrameWriter[T]

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    (Scala-specific) Adds output options for the underlying data source.

    (Scala-specific) Adds output options for the underlying data source.

    You can set the following option(s):

    • timeZone (default session local timezone): sets the string that indicates a timezone to be used to format timestamps in the JSON/CSV datasources or partition values.
    Since

    1.4.0

  29. def orc(path: String): Unit

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    Saves the content of the DataFrame in ORC format at the specified path.

    Saves the content of the DataFrame in ORC format at the specified path. This is equivalent to:

    format("orc").save(path)

    You can set the following ORC-specific option(s) for writing ORC files:

    • compression (default is the value specified in spark.sql.orc.compression.codec): compression codec to use when saving to file. This can be one of the known case-insensitive shorten names(none, snappy, zlib, and lzo). This will override orc.compress and spark.sql.orc.compression.codec. If orc.compress is given, it overrides spark.sql.orc.compression.codec.
    Since

    1.5.0

    Note

    Currently, this method can only be used after enabling Hive support

  30. def parquet(path: String): Unit

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    Saves the content of the DataFrame in Parquet format at the specified path.

    Saves the content of the DataFrame in Parquet format at the specified path. This is equivalent to:

    format("parquet").save(path)

    You can set the following Parquet-specific option(s) for writing Parquet files:

    • compression (default is the value specified in spark.sql.parquet.compression.codec): compression codec to use when saving to file. This can be one of the known case-insensitive shorten names(none, snappy, gzip, and lzo). This will override spark.sql.parquet.compression.codec.
    Since

    1.4.0

  31. def partitionBy(colNames: String*): DataFrameWriter[T]

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    Partitions the output by the given columns on the file system.

    Partitions the output by the given columns on the file system. If specified, the output is laid out on the file system similar to Hive's partitioning scheme. As an example, when we partition a dataset by year and then month, the directory layout would look like:

    • year=2016/month=01/
    • year=2016/month=02/

    Partitioning is one of the most widely used techniques to optimize physical data layout. It provides a coarse-grained index for skipping unnecessary data reads when queries have predicates on the partitioned columns. In order for partitioning to work well, the number of distinct values in each column should typically be less than tens of thousands.

    This is applicable for all file-based data sources (e.g. Parquet, JSON) staring Spark 2.1.0.

    Annotations
    @varargs()
    Since

    1.4.0

  32. def save(): Unit

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    Saves the content of the DataFrame as the specified table.

    Saves the content of the DataFrame as the specified table.

    Since

    1.4.0

  33. def save(path: String): Unit

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    Saves the content of the DataFrame at the specified path.

    Saves the content of the DataFrame at the specified path.

    Since

    1.4.0

  34. def saveAsTable(tableName: String): Unit

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    Saves the content of the DataFrame as the specified table.

    Saves the content of the DataFrame as the specified table.

    In the case the table already exists, behavior of this function depends on the save mode, specified by the mode function (default to throwing an exception). When mode is Overwrite, the schema of the DataFrame does not need to be the same as that of the existing table.

    When mode is Append, if there is an existing table, we will use the format and options of the existing table. The column order in the schema of the DataFrame doesn't need to be same as that of the existing table. Unlike insertInto, saveAsTable will use the column names to find the correct column positions. For example:

    scala> Seq((1, 2)).toDF("i", "j").write.mode("overwrite").saveAsTable("t1")
    scala> Seq((3, 4)).toDF("j", "i").write.mode("append").saveAsTable("t1")
    scala> sql("select * from t1").show
    +---+---+
    |  i|  j|
    +---+---+
    |  1|  2|
    |  4|  3|
    +---+---+

    In this method, save mode is used to determine the behavior if the data source table exists in Spark catalog. We will always overwrite the underlying data of data source (e.g. a table in JDBC data source) if the table doesn't exist in Spark catalog, and will always append to the underlying data of data source if the table already exists.

    When the DataFrame is created from a non-partitioned HadoopFsRelation with a single input path, and the data source provider can be mapped to an existing Hive builtin SerDe (i.e. ORC and Parquet), the table is persisted in a Hive compatible format, which means other systems like Hive will be able to read this table. Otherwise, the table is persisted in a Spark SQL specific format.

    Since

    1.4.0

  35. def sortBy(colName: String, colNames: String*): DataFrameWriter[T]

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    Sorts the output in each bucket by the given columns.

    Sorts the output in each bucket by the given columns.

    This is applicable for all file-based data sources (e.g. Parquet, JSON) staring Spark 2.1.0.

    Annotations
    @varargs()
    Since

    2.0

  36. final def synchronized[T0](arg0: ⇒ T0): T0

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  37. def text(path: String): Unit

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    Saves the content of the DataFrame in a text file at the specified path.

    Saves the content of the DataFrame in a text file at the specified path. The DataFrame must have only one column that is of string type. Each row becomes a new line in the output file. For example:

    // Scala:
    df.write.text("/path/to/output")
    
    // Java:
    df.write().text("/path/to/output")

    You can set the following option(s) for writing text files:

    • compression (default null): compression codec to use when saving to file. This can be one of the known case-insensitive shorten names (none, bzip2, gzip, lz4, snappy and deflate).
    Since

    1.6.0

  38. def toString(): String

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  39. final def wait(): Unit

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  40. final def wait(arg0: Long, arg1: Int): Unit

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  41. final def wait(arg0: Long): Unit

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