readSqlTable
Retrieves the schema for an SQL table using the provided database configuration.
Default Behavior:
If DbConnectionConfig.readOnly is true (which is the default), the connection will be:
explicitly set as read-only via
Connection.setReadOnly(true)used with
autoCommit = falseautomatically rolled back after reading, ensuring no changes to the database
Even if DbConnectionConfig.readOnly is set to false, the library still prevents data-modifying queries and only permits safe SELECT operations internally.
Return
the DataFrameSchema object representing the schema of the SQL table
Parameters
the database configuration to connect to the database, including URL, user, and password.
the name of the SQL table for which to retrieve the schema.
Retrieves the schema for an SQL table using the provided DataSource.
Example with HikariCP:
import com.zaxxer.hikari.HikariConfig
import com.zaxxer.hikari.HikariDataSource
val config = HikariConfig().apply {
jdbcUrl = "jdbc:postgresql://localhost:5432/mydb"
username = "user"
password = "password"
}
val dataSource = HikariDataSource(config)
// Get the schema for a specific table
val customersSchema = DataFrame.getSchemaForSqlTable(dataSource, "customers")
// Inspect the schema
println(customersSchema.columns)Return
the schema of the SQL table as a DataFrameSchema object.
Parameters
the DataSource to get a database connection from.
the name of the SQL table for which to retrieve the schema.
the type of database, could be a custom object, provided by user, optional, default is null, in that case the dbType will be recognized from the dataSource.
See also
Retrieves the schema for an SQL table using the provided database connection.
Return
the schema of the SQL table as a DataFrameSchema object.
Parameters
the database connection.
the name of the SQL table for which to retrieve the schema.
the type of database, could be a custom object, provided by user, optional, default is null, in that case the dbType will be recognized from the connection.
See also
Reads data from an SQL table and converts it into a DataFrame.
Note that if input dataframe contains duplicate column names, they will be automatically renamed in the resulting DataFrame.
Default Behavior:
If DbConnectionConfig.readOnly is true (which is the default), the connection will be:
explicitly set as read-only via
Connection.setReadOnly(true)used with
autoCommit = falseautomatically rolled back after reading, ensuring no changes to the database
Even if DbConnectionConfig.readOnly is set to false, the library still prevents data-modifying queries and only permits safe SELECT operations internally.
Return
the DataFrame containing the data from the SQL table.
Parameters
the configuration for the database, including URL, user, and password.
the name of the table to read data from.
the maximum number of rows to retrieve from the table. null (default) means no limit - all available rows will be fetched or positive integer (e.g., 100) - fetch at most that many rows
indicates how the column nullability should be inferred.
optional lambda to configure the PreparedStatement before execution. This allows for custom tuning of fetch size, query timeout, and other JDBC parameters.
Reads data from an SQL table and converts it into a DataFrame.
Note that if input dataframe contains duplicate column names, they will be automatically renamed in the resulting DataFrame.
Return
the DataFrame containing the data from the SQL table.
Parameters
the DataSource to get a database connection from.
the name of the table to read data from.
the maximum number of rows to retrieve from the table. null (default) means no limit - all available rows will be fetched or positive integer (e.g., 100) - fetch at most that many rows
indicates how the column nullability should be inferred.
the type of database, could be a custom object, provided by user, optional, default is null, in that case the dbType will be recognized from the dataSource.
optional lambda to configure the PreparedStatement before execution. This allows for custom tuning of fetch size, query timeout, and other JDBC parameters.
See also
Reads data from an SQL table and converts it into a DataFrame.
Note that if input dataframe contains duplicate column names, they will be automatically renamed in the resulting DataFrame.
Return
the DataFrame containing the data from the SQL table.
Parameters
the database connection to read tables from.
the name of the table to read data from.
the maximum number of rows to retrieve from the table. null (default) means no limit - all available rows will be fetched or positive integer (e.g., 100) - fetch at most that many rows
indicates how the column nullability should be inferred.
the type of database, could be a custom object, provided by user, optional, default is null, in that case the dbType will be recognized from the connection.
optional lambda to configure the PreparedStatement before execution. This allows for custom tuning of fetch size, query timeout, and other JDBC parameters.