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Version: 24.2.x

Connecting to Your Data

Dremio supports a variety of data sources, including data as code, metastores, local and cloud-based object storage, and databases.

Nessie Catalogs

Nessie catalogs enable you to process, manage, consume, and share data in the same way that code is shared during software development. That is, you are empowered to take control of your data using concepts including version control, commits, and testing and development in isolation from your production data.

Metastores

Object Storage

Databases

Dremio enables users to run external queries, queries that use the native syntax of the relational database, to process SQL statements that are not yet supported by Dremio or are too complex to convert. Dremio administrators enable the feature for each data source and specify which Dremio users can edit that source. See Querying Relational-Database Sources Directly for more information.

Dremio improves query performance for relational database datasets with Runtime Filtering, which applies dimension table filters to joined fact tables at runtime.

note
  • Decimal Support: Decimal-to-decimal mappings are supported for relational database sources.
  • Collation: Relational database sources must have a collation equivalent to LATIN1_GENERAL_BIN2 to ensure consistent results when operations are pushed down. For non-equivalent collations, create a view that coerces the collation to one that is equivalent to LATIN1_GENERAL_BIN2 and access that view.
  • For all sources, case-sensitive source data file/table names are not supported. In Dremio, case is ignored in the names of data files. file1.parquet, File1.parquet, and FILE1.parquet are considered to be equivalent names. Therefore, searching on one of these names can result in unanticipated results.
    In addition, columns in a table that have the same name with different cases are not supported. For example, if two columns named Trip_Pickup_DateTime and trip_pickup_datetime exist in the same table, one of the columns may disappear when the header is extracted.

Files and Directories

  • Formatting Data to a Table

  • Uploading Files

    note Case-sensitive source data file/table names are not supported. In Dremio, data filenames in your data source are "seen" in a case-insensitive manner. So, if you have three file names with difference cases (for example, `JOE` `Joe`, and `joe`), Dremio "sees" the files as having the same name. Thus, searching on `Joe`, `JOE`, or `joe`, can result in unanticipated data results.

    In addition, columns in a table that have the same name with different cases are not supported. For example, if two columns named `Trip_Pickup_DateTime` and `trip_pickup_datetime` exist in the same table, one of the columns may disappear when the header is extracted.