dataframe-jdbc/org.jetbrains.kotlinx.dataframe.io.db/Sqlite

Sqlite

class Sqlite(val customTypesMap: Map<String, SqliteCustomTypeConverter<*, *>> = emptyMap(), val customColumnsMap: Map<String, SqliteCustomTypeConverter<*, *>> = emptyMap()) : AdvancedDbType

Represents the Sqlite database type.

This class provides methods to convert data from a ResultSet to the appropriate type for Sqlite, and to generate the corresponding DataFrame schema.

Two levels of custom overrides are supported, with the following resolution order (first match wins):

customColumnsMap — keyed by the column name. Use this to override a specific column, regardless of its declared type.
customTypesMap — keyed by the declared SQL type name (as written in CREATE TABLE). Use this to override every column that shares a declared type.
The built-in SQLite conversion for BOOLEAN, DATE, DATETIME, TIME, TIMESTAMP, DECIMAL, NUMERIC and INT. This conversion is also applied to declared types that contain one of these names as a substring. So every column with SQLite's INTEGER affinity (INT, INTEGER, TINYINT, BIGINT, …) is read as Long. A REAL or TEXT value stored in such a column is not converted: reading the table throws.
The base DbType mapping.

Constructors

Sqlite

constructor(customTypesMap: Map<String, SqliteCustomTypeConverter<*, *>> = emptyMap(), customColumnsMap: Map<String, SqliteCustomTypeConverter<*, *>> = emptyMap())

Types

Companion

object Companion

Properties

customColumnsMap

val customColumnsMap: Map<String, SqliteCustomTypeConverter<*, *>>

customTypesMap

val customTypesMap: Map<String, SqliteCustomTypeConverter<*, *>>

dbTypeInJdbcUrl

val dbTypeInJdbcUrl: String

The name of the database as specified in the JDBC URL.

defaultFetchSize

open val defaultFetchSize: Int = 1000

Specifies the default batch size for fetching rows from the database during query execution.

defaultJdbcTypeToKTypeMapping

protected val defaultJdbcTypeToKTypeMapping: Map<Int, KType>

Default mapping of Java SQL Types to KType.

defaultQueryTimeout

open val defaultQueryTimeout: Int? = null

Specifies the default timeout in seconds for database queries.

driverClassName

open override val driverClassName: String

Represents the JDBC driver class name for a given database type.

tableTypes

open val tableTypes: List<String>?

The table type(s) (TABLE_TYPE) of ordinary tables in the SQL database, used by the readAllSqlTables functions as a filter when querying the database for all the tables it has using DatabaseMetaData.getTables.

Functions

buildDataColumn

override fun <D, P> buildDataColumn(name: String, values: List<D>, tableColumnMetadata: TableColumnMetadata, targetColumnSchema: ColumnSchema?, inferNullability: Boolean): DataColumn<P>

Builds a DataColumn from the given (preprocessed) values, adhering to targetColumnSchema.

buildSelectTableQueryWithLimit

open fun buildSelectTableQueryWithLimit(tableName: String, limit: Int?): String

Builds a SELECT query for reading from a table.

buildSqlQueryWithLimit

open fun buildSqlQueryWithLimit(sqlQuery: String, limit: Int = 1): String

Constructs a SQL query with a limit clause.

buildTableMetadata

open override fun buildTableMetadata(tables: ResultSet): TableMetadata

Builds the table metadata based on the database type and the ResultSet from the query.

configureReadStatement

open fun configureReadStatement(statement: PreparedStatement)

Configures the provided PreparedStatement for optimized read operations.

createConnection

open override fun createConnection(dbConfig: DbConnectionConfig): Connection

Creates a database connection using the provided configuration. This method is only called when working with DbConnectionConfig (internally managed connections).

generateConverter

protected open override fun generateConverter(tableColumnMetadata: TableColumnMetadata): AnyJdbcToDataFrameConverter

getConverter

protected open override fun getConverter(tableColumnMetadata: TableColumnMetadata): AnyJdbcToDataFrameConverter

getExpectedJdbcType

override fun getExpectedJdbcType(tableColumnMetadata: TableColumnMetadata): KType

Returns the type of the objects returned by getValueFromResultSet for the given column. Also called type J.

getPreprocessedValueType

override fun getPreprocessedValueType(tableColumnMetadata: TableColumnMetadata, expectedJdbcType: KType): KType

Returns the type of the objects returned by preprocessValue for the given column. Also called type D.

getTableColumnsMetadata

open fun getTableColumnsMetadata(resultSet: ResultSet): List<TableColumnMetadata>

Retrieves column metadata from a JDBC ResultSet.

getTargetColumnSchema

override fun getTargetColumnSchema(tableColumnMetadata: TableColumnMetadata, expectedValueType: KType): ColumnSchema?

Returns the target schema of the given column which buildDataColumn will adhere to. This schema corresponds to type P, in the sense that it will describe the schema of DataColumn<P>.

getValueFromResultSet

override fun <J> getValueFromResultSet(rs: ResultSet, columnIndex: Int, tableColumnMetadata: TableColumnMetadata, expectedJdbcType: KType): J

Extracts a value from the result set for the given column.

isSystemTable

open override fun isSystemTable(tableMetadata: TableMetadata): Boolean

Checks if the given table name is a system table for the specified database type.

preprocessValue

override fun <J, D> preprocessValue(value: J, tableColumnMetadata: TableColumnMetadata, expectedJdbcType: KType, expectedPreprocessedValueType: KType): D

(Potentially) preprocesses the value for the given column before collecting it in a DataFrame DataColumn.

quoteIdentifier

open fun quoteIdentifier(name: String): String

Quotes an identifier (table or column name) according to database-specific rules.

toDataColumn

protected fun <D, P> List<D>.toDataColumn(name: String, targetColumnSchema: ColumnSchema?, inferNullability: Boolean): DataColumn<P>

Helper function to convert this list of values to a DataColumn<P>.