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DATA_TYPES.md

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Data types

KExasol allows retrieving individual values from ExaStatementRow and ExaStreamExportRow using common getters for specific data types.

Getter Kotlin type Optimal for Exasol type
getBoolean Kotlin Boolean BOOLEAN
getDouble Kotlin Double DOUBLE PRECISION
getInt Kotlin Int DECIMAL(<9,0)
getLong Kotlin Long DECIMAL(<18,0)
getBigDecimal java.math.BigDecimal other DECIMAL
getString Kotlin String All types
getLocalDate java.time.LocalDate DATE
getLocalDateTime java.time.LocalDateTime TIMESTAMP

All common getters can return NULL.

Common getters can be used with column 0-based index or with column name. Please note: column names in Exasol are upper-cased in most of the cases.

For example:

row.getLong(0)                      // get first column as Long
row.getBigDecimal(1)                // get second column as BigDecimal
row.getString("USER_NAME")          // get column USER_NAME as String
row.getLocalDate("REGISTER_DATE")   // date column REGISTER_DATE as LocalDate

It is also possible to extract the whole row as a collection using special getters asList() and asMap().

For ExaStatementRow:

  • returned collections contain elements of data type Any?;
  • Exasol NULL values are represented as null;
  • Exasol BOOLEAN values are represented as Kotlin Boolean;
  • All other values are represented as type String;

For ExaStreamExportRow:

  • returned collections contain elements of data type String?;
  • Exasol NULL values are represented as null;
  • Exasol BOOLEAN values are represented as strings 1 and 0;
  • All others values are represented as type String;

Writing data types

While writing data using streamImport* functions, very similar setters are available. For example:

writer.setLong(0, 1L)                                                      // set first column as Long
writer.setString("USER_NAME", "abc")                                       // set column USER_NAME as String
writer.setLocalDate("REGISTER_DATE", LocalDate.parse("2020-01-01"))        // set column REGISTER_DATE as LocalDate
writer.writeRow()                                                          // flush row

It is also possible to write the whole row using List and Map collections:

writer.writeRow(
    listOf(1L, "abc", LocalDate.parse("2020-01-01"))
)

writer.writeRow(
    mapOf(
        "USER_ID" to 1L,
        "USER_NAME" to "abc",
        "REGISTER_DATE" to LocalDate.parse("2020-01-01")
    )
)

DATE and TIMESTAMP alternatives?

You are not forced to use LocalDate and LocalDateTime to represent Exasol DATE and TIMESTAMP types. You can use any other custom formatters and parsers instead. You can read and write temporal data using basic getString() and setString() and apply any required transformations.

Examples

Please check examples 01_fetch.kt and 02_stream.kt for more details.