sqldb/sqlc: add chain_param schema and queries

diff --git a/sqldb/migrations.go b/sqldb/migrations.go
index 395bd66..241e5c0 100644
--- a/sqldb/migrations.go
+++ b/sqldb/migrations.go
@@ -131,6 +131,11 @@ var (
 			Version:       17,
 			SchemaVersion: 14,
 		},
+		{
+			Name:          "000015_chain_params",
+			Version:       18,
+			SchemaVersion: 15,
+		},
 	}, migrationAdditions...)
 
 	// ErrMigrationMismatch is returned when a migrated record does not
diff --git a/sqldb/sqlc/chain_params.sql.go b/sqldb/sqlc/chain_params.sql.go
new file mode 100644
index 0000000..bb7b442
--- /dev/null
+++ b/sqldb/sqlc/chain_params.sql.go
@@ -0,0 +1,33 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.29.0
+// source: chain_params.sql
+
+package sqlc
+
+import (
+	"context"
+)
+
+const getChainNetwork = `-- name: GetChainNetwork :one
+SELECT network FROM chain_params
+WHERE single_row = TRUE
+`
+
+func (q *Queries) GetChainNetwork(ctx context.Context) (string, error) {
+	row := q.db.QueryRowContext(ctx, getChainNetwork)
+	var network string
+	err := row.Scan(&network)
+	return network, err
+}
+
+const insertChainNetwork = `-- name: InsertChainNetwork :exec
+INSERT INTO chain_params (single_row, network)
+VALUES (TRUE, $1)
+ON CONFLICT (single_row) DO NOTHING
+`
+
+func (q *Queries) InsertChainNetwork(ctx context.Context, network string) error {
+	_, err := q.db.ExecContext(ctx, insertChainNetwork, network)
+	return err
+}
diff --git a/sqldb/sqlc/migrations/000015_chain_params.down.sql b/sqldb/sqlc/migrations/000015_chain_params.down.sql
new file mode 100644
index 0000000..4624cf8
--- /dev/null
+++ b/sqldb/sqlc/migrations/000015_chain_params.down.sql
@@ -0,0 +1 @@
+DROP TABLE IF EXISTS chain_params;
diff --git a/sqldb/sqlc/migrations/000015_chain_params.up.sql b/sqldb/sqlc/migrations/000015_chain_params.up.sql
new file mode 100644
index 0000000..cf2a3f6
--- /dev/null
+++ b/sqldb/sqlc/migrations/000015_chain_params.up.sql
@@ -0,0 +1,8 @@
+-- The chain_params table stores chain-level properties of the database. It is
+-- used to persist and validate chain-specific invariants across restarts, such
+-- as which Bitcoin network the database was initialised for. The single_row
+-- column is a boolean primary key that enforces exactly one row in the table.
+CREATE TABLE IF NOT EXISTS chain_params (
+    single_row BOOLEAN PRIMARY KEY DEFAULT TRUE CHECK (single_row),
+    network    TEXT    NOT NULL
+);
diff --git a/sqldb/sqlc/models.go b/sqldb/sqlc/models.go
index 513f045..ef9aa90 100644
--- a/sqldb/sqlc/models.go
+++ b/sqldb/sqlc/models.go
@@ -28,6 +28,11 @@ type AmpSubInvoiceHtlc struct {
 	Preimage   []byte
 }
 
+type ChainParam struct {
+	SingleRow bool
+	Network   string
+}
+
 type GraphChannel struct {
 	ID                int64
 	Version           int16
diff --git a/sqldb/sqlc/querier.go b/sqldb/sqlc/querier.go
index 3c16292..9b95a66 100644
--- a/sqldb/sqlc/querier.go
+++ b/sqldb/sqlc/querier.go
@@ -103,6 +103,7 @@ type Querier interface {
 	FilterPayments(ctx context.Context, arg FilterPaymentsParams) ([]FilterPaymentsRow, error)
 	FilterPaymentsDesc(ctx context.Context, arg FilterPaymentsDescParams) ([]FilterPaymentsDescRow, error)
 	GetAMPInvoiceID(ctx context.Context, setID []byte) (int64, error)
+	GetChainNetwork(ctx context.Context) (string, error)
 	GetChannelAndNodesBySCID(ctx context.Context, arg GetChannelAndNodesBySCIDParams) (GetChannelAndNodesBySCIDRow, error)
 	GetChannelByOutpointWithPolicies(ctx context.Context, arg GetChannelByOutpointWithPoliciesParams) (GetChannelByOutpointWithPoliciesRow, error)
 	GetChannelBySCID(ctx context.Context, arg GetChannelBySCIDParams) (GraphChannel, error)
@@ -168,6 +169,7 @@ type Querier interface {
 	HighestSCID(ctx context.Context, version int16) ([]byte, error)
 	InsertAMPSubInvoice(ctx context.Context, arg InsertAMPSubInvoiceParams) error
 	InsertAMPSubInvoiceHTLC(ctx context.Context, arg InsertAMPSubInvoiceHTLCParams) error
+	InsertChainNetwork(ctx context.Context, network string) error
 	InsertChannelFeature(ctx context.Context, arg InsertChannelFeatureParams) error
 	// NOTE: This query is only meant to be used by the graph SQL migration since
 	// for that migration, in order to be retry-safe, we don't want to error out if
diff --git a/sqldb/sqlc/queries/chain_params.sql b/sqldb/sqlc/queries/chain_params.sql
new file mode 100644
index 0000000..596ff4b
--- /dev/null
+++ b/sqldb/sqlc/queries/chain_params.sql
@@ -0,0 +1,8 @@
+-- name: InsertChainNetwork :exec
+INSERT INTO chain_params (single_row, network)
+VALUES (TRUE, sqlc.arg(network))
+ON CONFLICT (single_row) DO NOTHING;
+
+-- name: GetChainNetwork :one
+SELECT network FROM chain_params
+WHERE single_row = TRUE;