Dimensions

A dimension represents some characteristic of your data, and dimensions define the hyperspace of the array.

Dimensions define the hyperspace of the array, in which cells are stored and efficiently retrieved. You can think of dimensions as the fields of a dataset that receive the majority of the query conditions, since TileDB is designed to perform range search on these dimensions very fast. Dimensions differ from attributes, which define the values that TileDB stores inside the multi-dimensional cells. Visit the Performance: Dimensions vs. Attributes section for information about how to choose the dimensions and attributes when creating an array for your dataset.

The array data model (dense and sparse) The array data model (dense and sparse)

The dimensions also define the cell coordinates in sparse arrays. Contrary to dense arrays, sparse arrays in TileDB do not materialize empty cells on storage. Therefore, there has to be a way to know the cells to which the non-empty cells correspond. To achieve this, TileDB materializes the cell coordinates of the non-empty cells, which depend on the number and data types of the dimensions. Visit the Array Data Model, Key Concepts: Data Layout and Storage Format Spec sections for more information on how TileDB stores the cell coordinates in sparse arrays.

The following table summarizes the supported dimension data types for dense and sparse arrays.

Datatype Description Array type
TILEDB_STRING_ASCII Variable length string Sparse
TILEDB_INT8 8-bit integer Dense & Sparse
TILEDB_UINT8 8-bit unsigned integer Dense & Sparse
TILEDB_INT16 16-bit integer Dense & Sparse
TILEDB_UINT16 16-bit unsigned integer Dense & Sparse
TILEDB_INT32 32-bit integer Dense & Sparse
TILEDB_UINT32 32-bit unsigned integer Dense & Sparse
TILEDB_INT64 64-bit integer Dense & Sparse
TILEDB_UINT64 64-bit unsigned integer Dense & Sparse
TILEDB_FLOAT32 32-bit floating point Sparse
TILEDB_FLOAT64 64-bit floating point Sparse
TILEDB_DATETIME_YEAR Years Dense & Sparse
TILEDB_DATETIME_MONTH Months Dense & Sparse
TILEDB_DATETIME_WEEK Weeks Dense & Sparse
TILEDB_DATETIME_DAY Days Dense & Sparse
TILEDB_DATETIME_HR Hours Dense & Sparse
TILEDB_DATETIME_MIN Minutes Dense & Sparse
TILEDB_DATETIME_SEC Seconds Dense & Sparse
TILEDB_DATETIME_MS Milliseconds Dense & Sparse
TILEDB_DATETIME_US Microseconds Dense & Sparse
TILEDB_DATETIME_NS Nanoseconds Dense & Sparse
TILEDB_DATETIME_PS Picoseconds Dense & Sparse
TILEDB_DATETIME_FS Femtoseconds Dense & Sparse
TILEDB_DATETIME_AS Attoseconds Dense & Sparse
Datatype Description Array type
Datatype.StringAscii Variable length string Sparse
Datatype.Int8 8-bit integer Dense & Sparse
Datatype.UInt8 8-bit unsigned integer Dense & Sparse
Datatype.Int16 16-bit integer Dense & Sparse
Datatype.UInt16 16-bit unsigned integer Dense & Sparse
Datatype.Int32 32-bit integer Dense & Sparse
Datatype.UInt32 32-bit unsigned integer Dense & Sparse
Datatype.Int64 64-bit integer Dense & Sparse
Datatype.UInt64 64-bit unsigned integer Dense & Sparse
Datatype.Float32 32-bit floating point Sparse
Datatype.Float64 64-bit floating point Sparse
DataType.DateTimeYear Years Dense & Sparse
DataType.DateTimeMonth Months Dense & Sparse
DataType.DateTimeWeek Weeks Dense & Sparse
DataType.DateTimeDay Days Dense & Sparse
DataType.DateTimeHour Hours Dense & Sparse
DataType.DateTimeMinute Minutes Dense & Sparse
DataType.DateTimeMillisecond Milliseconds Dense & Sparse
DataType.DateTimeMicrosecond Microseconds Dense & Sparse
DataType.DateTimeNanosecond Nanoseconds Dense & Sparse
DataType.DateTimePicosecond Picoseconds Dense & Sparse
DataType.DateTimeFemtosecond Femtoseconds Dense & Sparse
DataType.DateTimeAttosecond Attoseconds Dense & Sparse
Datatype Description Array type
"ascii" Variable length string Sparse
np.int8 8-bit integer Dense & Sparse
np.uint8 8-bit unsigned integer Dense & Sparse
np.int16 16-bit integer Dense & Sparse
np.uint16 16-bit unsigned integer Dense & Sparse
np.int32 32-bit integer Dense & Sparse
np.uint32 32-bit unsigned integer Dense & Sparse
np.int64 64-bit integer Dense & Sparse
np.uint64 64-bit unsigned integer Dense & Sparse
np.float32 32-bit floating point Sparse
np.float64 64-bit floating point Sparse
"datetime64[Y]" Years Dense & Sparse
"datetime64[M]" Months Dense & Sparse
"datetime64[W]" Weeks Dense & Sparse
"datetime64[D]" Days Dense & Sparse
"datetime64[h]" Hours Dense & Sparse
"datetime64[m]" Minutes Dense & Sparse
"datetime64[s]" Seconds Dense & Sparse
"datetime64[ms]" Milliseconds Dense & Sparse
"datetime64[us]" Microseconds Dense & Sparse
"datetime64[ns]" Nanoseconds Dense & Sparse
"datetime64[ps]" Picoseconds Dense & Sparse
"datetime64[fs]" Femtoseconds Dense & Sparse
"datetime64[as]" Attoseconds Dense & Sparse
Datatype Description Array type
"ASCII" Variable length string Sparse
"INT8" 8-bit integer Dense & Sparse
"UINT8" 8-bit unsigned integer Dense & Sparse
"INT16" 16-bit integer Dense & Sparse
"UINT16" 16-bit unsigned integer Dense & Sparse
"INT32" 32-bit integer Dense & Sparse
"UINT32" 32-bit unsigned integer Dense & Sparse
"INT64" 64-bit integer Dense & Sparse
"UINT64" 64-bit unsigned integer Dense & Sparse
"FLOAT32" 32-bit floating point Sparse
"FLOAT64" 64-bit floating point Sparse
"DATETIME_YEAR" Years Dense & Sparse
"DATETIME_MONTH" Months Dense & Sparse
"DATETIME_WEEK" Weeks Dense & Sparse
"DATETIME_DAY" Days Dense & Sparse
"DATETIME_HR" Hours Dense & Sparse
"DATETIME_MIN" Minutes Dense & Sparse
"DATETIME_SEC" Seconds Dense & Sparse
"DATETIME_MS" Milliseconds Dense & Sparse
"DATETIME_US" Microseconds Dense & Sparse
"DATETIME_NS" Nanoseconds Dense & Sparse
"DATETIME_PS" Picoseconds Dense & Sparse
"DATETIME_FS" Femtoseconds Dense & Sparse
"DATETIME_AS" Attoseconds Dense & Sparse