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DatabaseReference   
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DatabaseReference

Listing of Supported Databases »
Unsupported in Public Cloud[Experimental]

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DatabaseReference[File["filename"]]

represents a reference to a local file-based SQL database.

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represents a reference to a server-based SQL database.

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represents a fully specified reference to any SQL database.

Details

  • DatabaseReference[…] includes information on how to connect to a database, but does not actually perform the connection. The connection is automatically performed by functions like RelationalDatabase, as well as by database querying functions such EntityValue.
  • In DatabaseReference[URL["url"]], "url" is typically of the form "backend://user:password@host:port/name".
  • In DatabaseReference[File["path"]], "path" is the path to an SQLite database file.
  • In DatabaseReference[assoc], typical elements of assoc include:
  • "Backend"the type of SQL backend used
    "Name"the name of the database, or path to it
    "Host"the host serving the database
    "Port"the server port through which to access the database
    "Username"the username used to authenticate the database
    "Password"the password used to authenticate the database
  • Possible values for "Backend" include "SQLite", "PostgreSQL", "MySQL", "MicrosoftSQL", "Oracle".
  • For file-based databases such as SQLite, "Name" gives the path to the file containing the database. If "Name" is not provided, an in-memory database is used.
  • For server-based databases, "Name" gives the name of the database at the specified endpoint.
  • For file-based databases, no values need to be specified for "Host" and "Port".
  • For server-based databases, "Host" can be a network host name or an IP address, specified with a string or using an IPAddress object.
  • If no value for "Port" is specified, a default for each type of backend will be used.
  • DatabaseReference[…][prop] gives information about the database being referenced.
  • The property prop can be any of the elements that can be supplied in DatabaseReference[assoc].

Examples

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Basic Examples  (4)Summary of the most common use cases

Construct a DatabaseReference from a file:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-whmgd1
Out[1]=1

Construct a DatabaseReference from a URL:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-pgvlrw
Out[1]=1

Construct a DatabaseReference from an Association:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-l0u85z
Out[1]=1

Execute SQL commands using ExternalEvaluate:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-j4gt81
Out[1]=1

Scope  (1)Survey of the scope of standard use cases

Extract properties from a DatabaseReference:

In[2]:=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-emx228
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-f3xd6f
Out[3]=3

Multiple properties can be extracted at once:

In[4]:=4
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-xxvs8c
Out[4]=4

Applications  (4)Sample problems that can be solved with this function

Use in conjunction with RelationalDatabase to extract the schema of a database:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-ury1qj
Out[1]=1

Construct an EntityStore from the RelationalDatabase object:

In[2]:=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-fbzaue
Out[2]=2

Register the EntityStore:

In[3]:=3
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-eshjaz
Out[3]=3

Perform a query:

In[5]:=5
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-m6brmt
Out[5]=5

Open a database connection by using StartExternalSession:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-hctz76
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-nt76oa
Out[2]=2

Delete the session to disconnect:

In[3]:=3
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-2amn4m

Use ExternalEvaluate to open a connection, run a query and close the connection:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-t75x55
Out[1]=1

DatabaseReference can also represent an in-memory SQLite database:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-20uc3
Out[1]=1

All operations done over an in-memory session are lost at the end of the ExternalEvaluate call:

In[2]:=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-zfcecb
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-7qce5o
Out[3]=3

Properties & Relations  (1)Properties of the function, and connections to other functions

Construct a DatabaseReference pointing to a file:

In[1]:=1
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-laiezk
Out[1]=1

Connect manually to the database:

In[2]:=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-89cjqf
Out[2]=2

And disconnect:

In[3]:=3
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-rofid9
Out[3]=3

Possible Issues  (1)Common pitfalls and unexpected behavior

A DatabaseReference does not guarantee the existence of the database:

In[2]:=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-lkzhcj
Out[2]=2
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https://wolfram.com/xid/0bc6ixhb1ft1p1e-rph49t
Wolfram Research (2019), DatabaseReference, Wolfram Language function, https://reference.wolfram.com/language/ref/DatabaseReference.html.
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Wolfram Research (2019), DatabaseReference, Wolfram Language function, https://reference.wolfram.com/language/ref/DatabaseReference.html.

Text

Wolfram Research (2019), DatabaseReference, Wolfram Language function, https://reference.wolfram.com/language/ref/DatabaseReference.html.

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Wolfram Research (2019), DatabaseReference, Wolfram Language function, https://reference.wolfram.com/language/ref/DatabaseReference.html.

CMS

Wolfram Language. 2019. "DatabaseReference." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/DatabaseReference.html.

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Wolfram Language. 2019. "DatabaseReference." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/DatabaseReference.html.

APA

Wolfram Language. (2019). DatabaseReference. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/DatabaseReference.html

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Wolfram Language. (2019). DatabaseReference. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/DatabaseReference.html

BibTeX

@misc{reference.wolfram_2025_databasereference, author="Wolfram Research", title="{DatabaseReference}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/DatabaseReference.html}", note=[Accessed: 09-May-2025 ]}

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@misc{reference.wolfram_2025_databasereference, author="Wolfram Research", title="{DatabaseReference}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/DatabaseReference.html}", note=[Accessed: 09-May-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_databasereference, organization={Wolfram Research}, title={DatabaseReference}, year={2019}, url={https://reference.wolfram.com/language/ref/DatabaseReference.html}, note=[Accessed: 09-May-2025 ]}

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@online{reference.wolfram_2025_databasereference, organization={Wolfram Research}, title={DatabaseReference}, year={2019}, url={https://reference.wolfram.com/language/ref/DatabaseReference.html}, note=[Accessed: 09-May-2025 ]}