Query the Data Delivery Network
Query the DDNThe easiest way to query any data on Splitgraph is via the "Data Delivery Network" (DDN). The DDN is a single endpoint that speaks the PostgreSQL wire protocol. Any Splitgraph user can connect to it at data.splitgraph.com:5432
and query any version of over 40,000 datasets that are hosted or proxied by Splitgraph.
For example, you can query the defaulted_tax_data
table in this repository, by referencing it like:
"sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest"."defaulted_tax_data"
or in a full query, like:
SELECT
":id", -- Socrata column ID
"mailaddress2", -- Address line 2 except when MailAddress1 is C/O or DBA.
"mailaddress1", -- Address line 1 or C/O or DBA (Doing Business As)
"defaultamt", -- 1st year of defaulted tax and penalties. Base Tax amount + Ten Percent Penalty + Cost Charge
"assessment_roll_year", -- The year the bill was placed on the tax roll.
"location_city_state", -- The city state location of the property.
"location_address", -- The street address location of the property.
"collection_code2", -- Set when payment is recorded.
"fullredemptionpaid", -- Prior year taxes paid.
"exemption_code1", -- Code = Description, E01 = Homeowner, E04 = Disabled Vet Spouse 100,000, E06 = Disabled Vet 100,000, E08 = Welfare-Charitable, E16 = Cemetery, E17 = Church, E18 = Free Museum/Library, E21 = Public School, E22 = Religious-One Time Filing, E97 = Hox Penalty (used for roll corrections), E99 = Low Value
"billednetvalue", -- The billed net value of the assessment.
"billedgrowingimprvalue", -- Assessment billed for agricultural improvements value on property.
"billedfixedimprvalue", -- Assessment billed for fixed improvements value on property.
"billedmarketlandvalue", -- Bill value. If an original bill, amount represents total value. If original bill is paid, amount represents net change. If reassessment results in a lower value, amount shown could be negative.
"salenoticedate", -- When property becomes 5 years delinquent and the tax collector records the power to sell.
"mailaddress3", -- Address line 2 when MailAddress1 is C/O or DBA. In all other cases City, State, zip
"defaultnum", -- Systematically assigned number for secured records that go unpaid past their fiscal year.
"secured_delinq_penality_amt_paid", -- The interest calculated for assessment from July 1st of the fiscal year through paid as of date.
"billedpersonalpropmhvalue", -- he billed amount of personal property mobile home value on the assessment.
"billedpersonalpropvalue", -- The billed amount of personal property value on the assessment.
"taxability", -- Code = Description, 0 = Normal Ownership, 1 = Business, Ownership, 2 = Zero Value Property, 10 = Senior Citizens Postponement, 12 = Low Value Real Property, 34 = Taxable Gov’t Entity Section 11, 44 = Gov’t Restricted Affordable Housing, 50 = Property Under CLCA, 51 = Property under CLCA/Business, 60 = Tax Postponed (Sr Citizens Postponement), 70 = Common Area, 600 = Timber Preserve, 800 = Prop 8 Reduction-Manual, 801 = Prop 8 Reduction w Bus/Manual, 850 = Prop 8 w/Contract CLCA, 860 = Prop 8 Tax Postponed, 870 = Prop 8 Value Uploaded, 871 = Prop 8 Automatic Reduction w/business
"originating_assessment_number", -- The original assessment number on parcel splits.
"originating_assessment", -- The parcel that originated the tax bill.
"assessment_number", -- 1st 3 Characters = Book, 2nd 3 Characters = Page, 3rd 3 Characters = Parcel, 4th 3 Characters = Sub Parcel
"base_tax_amount", -- Total tax amount for the 2nd installment.
"redeemed_date", -- Date default record is payed.
"feeparcel", -- The parcel where the assessment is located.
"taxyear", -- Tax rate year.
"tax_rate_area", -- The original tax rate area for a delinquent assessment.
"exemption_amount2", -- The amount of the exemption
"mailaddress4", -- Address line 3 when MailAddr1 is C/O or DBA.
"paid_amount", -- This represents the tax amount paid - Base_Tax_Amount + Ten_Percent_Penalty_Amount (if paid) + Cost_Charge (if paid) for redemptions.
"isagpreserve", -- The property is an agricultural preserve.
"default_date", -- The date the assessment defaulted.
"ten_percent_penality_amount", -- Penalty amount for the Base_Tax_Amount. Always set, delinquent or not.
"exemption_amount1", -- The amount of the exemption.
"billedstructuralimprvalue", -- Assessment billed for structural improvements value on property.
"redemption_fee",
"bill_date", -- The date the bill was printed.
"exemption_code2", -- Code = Description, E01 = Homeowner, E04 = Disabled Vet Spouse 100,000, E06 = Disabled Vet 100,000, E08 = Welfare-Charitable, E16 = Cemetery, E17 = Church, E18 = Free Museum/Library, E21 = Public School, E22 = Religious-One Time Filing, E97 = Hox Penalty (used for roll corrections), E99 = Low Value
"existsbankruptcy", -- A bankruptcy exists on the assessment.
"cost_charge", -- Second installment penalty cost charge.
"redemptiontotalfees" -- Total redemption fees paid.
FROM
"sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest"."defaulted_tax_data"
LIMIT 100;
Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7
with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.sonomacounty.ca.gov. When you querysonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest
on the DDN, we "mount" the repository using the socrata
mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).
We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT
is only guaranteed for subsequent queries that land on the same node.
Query Your Local Engine
bash -c "$(curl -sL https://github.com/splitgraph/splitgraph/releases/latest/download/install.sh)"
Read the installation docs.
Splitgraph Cloud is built around Splitgraph Core (GitHub), which includes a local Splitgraph Engine packaged as a Docker image. Splitgraph Cloud is basically a scaled-up version of that local Engine. When you query the Data Delivery Network or the REST API, we mount the relevant datasets in an Engine on our servers and execute your query on it.
It's possible to run this engine locally. You'll need a Mac, Windows or Linux system to install sgr
, and a Docker installation to run the engine. You don't need to know how to actually use Docker; sgr
can manage the image, container and volume for you.
There are a few ways to ingest data into the local engine.
For external repositories (like this repository), the Splitgraph Engine can "mount" upstream data sources by using sgr mount
. This feature is built around Postgres Foreign Data Wrappers (FDW). You can write custom "mount handlers" for any upstream data source. For an example, we blogged about making a custom mount handler for HackerNews stories.
For hosted datasets, where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr clone
and sgr checkout
.
Mounting Data
This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.sonomacounty.ca.gov, and Splitgraph indexes it. This means it is not an actual Splitgraph image, so you cannot use sgr clone
to get the data. Instead, you can use the socrata
adapter with the sgr mount
command. Then, if you want, you can import the data and turn it into a Splitgraph image that others can clone.
First, install Splitgraph if you haven't already.
Mount the table with sgr mount
sgr mount socrata \
"sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7" \
--handler-options '{
"domain": "data.sonomacounty.ca.gov",
"tables": {
"defaulted_tax_data": "bp8v-uax7"
}
}'
That's it! Now you can query the data in the mounted table like any other Postgres table.
Query the data with your existing tools
Once you've loaded the data into your local Splitgraph engine, you can query it with any of your existing tools. As far as they're concerned, sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7
is just another Postgres schema.