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Data models

Understanding Prequel models

What are data models?

In this documentation, a data model refers to the Prequel representation of the structured data to be transferred using Prequel. An individual data model usually represents a single table, though (depending on the source/destination) it may also refer to a JSON blob or other file format (e.g., Parquet, CSV).

A Prequel data model represents the data structure that is read from a source and written to a destination

A Prequel data model represents the data structure that is read from a source and written to a destination

Data model configuration

Each Prequel data model is configured via a JSON file with a specific format. If no model_name is provided, the name of the file (not including the extension) will be the name used for the table in the destination database. For example, for the configuration below, the destination table will appear as logs.

{
  "model_name": "logs",
  "columns": [
    {
      "name_in_source": "id",
      "name_in_destination": "id",
      "data_type": "text",
      "is_primary_key": true
    },
    {
      "name_in_source": "log",
      "name_in_destination": "event_log",
      "description":"A descriptive text entry of the event that occured.",
      "data_type": "text"
    },
    {
      "name_in_source": "updated_at",
      "name_in_destination": "updated_at",
      "data_type": "timestamp",
      "is_last_modified": true
    }
  ],
  "source_table": "source_schema.application_logs",
  "source_name": "Example Production Source",
  "organization_column": "organization_id"
}

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Syncing config files from GitHub

You can leverage the Prequel GitHub Action to automatically sync any config file changes from GitHub to Prequel.

Configuration file keys

Each configuration file has 6 top level config keys: (3 required) columns, source_table, and organization_column, and (3 optional) model_name, description, and source_name.

Config file keys

Config KeyRequiredDescription
model_nameName of table to be loaded into the destination. If left blank, the file name (not including file extension) will be used.
descriptionTable description. Will be applied to destination tables if provided.
columnsA list of all destination columns (for this destination table). This is used to CREATE the table in the destination database, so it is important to use accurate types that correspond to the source data. The order of this list dictates the order in which columns appear in the destination database.

These columns are also used to create the READ and WRITE query, so it is important to use the correct name_in_source and a descriptive name_in_destination for end customers. They can, but do not need to be, the same name.

is_primary_key and is_last_modified are two important column flags that indicate which columns to use for detecting changes and propagating changes to the correct row in the destination. One of each must be present on one of the column objects.
source_tableSpecifies the name of the source table to be queried.
source_nameSpecifies the source from which this model should read data. This field is only required if multiple sources exist in the account. If left blank and only one source exists, models will read from that source by default.
organization_columnSpecifies the column that will be used for filtering data by organization. Because this column is not necessarily a column that you want to transfer to users, it is not required within the columns list (unlike is_primary_key and is_last_modified). This column must be a string or varchar (non-numeric) data type.

Column object keys

Column object keyRequiredDescription
name_in_source
name_in_destination
data_type
is_primary_key(On exactly one column)
is_last_modified(On exactly one column)
description

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Using Acceptable Types

It is important to use the correct data_type for each column to ensure compatibility with all destinations. Refer to the Data Types documentation for the complete list of supported types.
By default, every destination you add to Prequel will be sent all the models defined in the prequel/models directory. Products allow you to only send a subset of those models to destinations.

Reserved column names

Some reserved keywords cannot be used as column names due to reserved statuses in common destination systems. There are 334:

1-6768-134135-201202-268269-334
ACCESSIBLEDEFERRABLEINOUTNULLSMALLINT
ACCOUNTDEFINEINSENSITIVENULLSSOME
ADDDELAYEDINSERTNUMERICSPATIAL
ALLDELETEINTOFSPECIFIC
ALTERDENSE_RANKINT1OFFSETSQL
ANALYSEDESCINT2ONSQL_BIG_RESULT
ANALYZEDESCRIBEINT3ONLYSQL_CALC_FOUND_ROWS
ANDDETERMINISTICINT4OPTIMIZESQL_SMALL_RESULT
ANTIDISTINCTINT8OPTIMIZER_COSTSSQLEXCEPTION
ANYDISTINCTROWINTEGEROPTIONSQLSTATE
ARRAYDIVINTERSECTOPTIONALLYSQLWARNING
ASDOINTERVALORSSL
ASCDOUBLEINTOORDERSTART
ASENSITIVEDROPIO_AFTER_GTIDSORGANIZATIONSTARTING
ASSERT_ROWS_MODIFIEDDUALIO_BEFORE_GTIDSOUTSTORED
ASYMMETRICEACHISOUTERSTRAIGHT_JOIN
ATELSEISNULLOUTFILESTRUCT
AUTHORIZATIONELSEIFISSUEOVERSYMMETRIC
BEFOREEMPTYITERATEOVERLAPSSYSTEM
BETWEENENCLOSEDJOINPARTITIONTABLE
BIGINTENDJSON_TABLEPERCENT_RANKTABLESAMPLE
BINARYENUMKEYPLACINGTERMINATED
BLOBESCAPEKEYSPRECEDINGTHEN
BOTHESCAPEDKILLPRECISIONTINYBLOB
BYEXCEPTLAGPRIMARYTINYINT
CALLEXCLUDELAST_VALUEPROCEDURETINYTEXT
CASCADEEXISTSLATERALPROTOTO
CASEEXITLEADPURGETRAILING
CASTEXPLAINLEADINGQUALIFYTREAT
CHANGEEXTRACTLEAVERANGETRIGGER
CHARFALSELEFTRANKTRUE
CHARACTERFETCHLIKEREADUNBOUNDED
CHECKFIRST_VALUELIMITREAD_WRITEUNDO
COLLATEFLOATLINEARREADSUNION
COLLATIONFLOAT4LINESREALUNIQUE
COLUMNFLOAT8LOADRECURSIVEUNLOCK
CONCURRENTLYFOLLOWINGLOCALTIMEREFERENCESUNNEST
CONDITIONFORLOCALTIMESTAMPREGEXPUNSIGNED
CONNECTFORCELOCKRELEASEUPDATE
CONNECTIONFOREIGNLONGRENAMEUSAGE
CONSTRAINTFREEZELONGBLOBREPEATUSE
CONTAINSFROMLONGTEXTREPLACEUSER
CONTINUEFULLLOOKUPREQUIREUSING
CONVERTFULLTEXTLOOPRESIGNALUTC_DATE
CREATEFUNCTIONLOW_PRIORITYRESTRICTUTC_TIME
CROSSGENERATEDMASTER_BINDRETURNUTC_TIMESTAMP
CUBEGETMASTER_SSL_VERIFY_SERVER_CERTRETURNINGVALUES
CUME_DISTGRANTMATCHREVOKEVARBINARY
CURRENTGROUPMAXVALUERIGHTVARCHAR
CURRENT_CATALOGGROUPINGMEDIUMBLOBRLIKEVARCHARACTER
CURRENT_DATEGROUPSMEDIUMINTROLLUPVARIADIC
CURRENT_ROLEGSCLUSTERMEDIUMTEXTROWVARYING
CURRENT_SCHEMAHASHMERGEROW_NUMBERVERBOSE
CURRENT_TIMEHAVINGMIDDLEINTROWSVIEW
CURRENT_TIMESTAMPHIGH_PRIORITYMINUSSAMPLEVIRTUAL
CURRENT_USERHOUR_MICROSECONDMINUTE_MICROSECONDSCHEMAWHEN
CURSORHOUR_MINUTEMINUTE_SECONDSCHEMASWHENEVER
DATABASEHOUR_SECONDMODSECOND_MICROSECONDWHERE
DATABASESIFMODIFIESSELECTWHILE
DAY_HOURIGNORENATURALSEMIWINDOW
DAY_MICROSECONDILIKENEWSENSITIVEWITH
DAY_MINUTEINNOSEPARATORWITHIN
DAY_SECONDINCREMENTNO_WRITE_TO_BINLOGSESSION_USERWRITE
DECINDEXNOTSETXOR
DECIMALINFILENOTNULLSHOWYEAR_MONTH
DECLAREINITIALLYNTH_VALUESIGNALZEROFILL
DEFAULTINNERNTILESIMILAR``

Grouping data models into products

By default, every destination you add to Prequel will be sent all configured models. Products allow you to only send a subset of those models to destinations.