WIP on remove fields

src/main/kotlin/Parameters.kt

@@ -98,4 +98,23 @@ object Parameters {
             throw DocumentException("Error creating query / binding parameters: ${ex.message}", ex)
         }
     }
+
+    /**
+     * Create parameters for field names to be removed from a document
+     *
+     * @param names The names of the fields to be removed
+     * @param parameterName The parameter name to use for the query
+     * @return A list of parameters to use for building the query
+     */
+    fun fieldNames(names: Collection<String>, parameterName: String = ":name") =
+        when (Configuration.dialect("generate field name parameters")) {
+            Dialect.POSTGRESQL -> listOf(Parameter(parameterName, ParameterType.STRING, if (names.size == 1) {
+                    names.elementAt(0)
+                } else {
+                    names.joinToString(",").let { "{$it}" }
+                }))
+            Dialect.SQLITE -> names.mapIndexed { index, name ->
+                Parameter("$parameterName$index", ParameterType.STRING, name)
+            }
+        }
 }

src/main/kotlin/query/Patch.kt

@@ -51,7 +51,7 @@ object Patch {
      * @param tableName The name of the table where the document is stored
      * @return A query to patch JSON documents by JSON containment
      */
-    fun <TKey> byContains(tableName: String) =
+    fun byContains(tableName: String) =
         statementWhere(patch(tableName), Where.jsonContains())
 
     /**
@@ -60,6 +60,6 @@ object Patch {
      * @param tableName The name of the table where the document is stored
      * @return A query to patch JSON documents by JSON path match
      */
-    fun <TKey> byJsonPath(tableName: String) =
+    fun byJsonPath(tableName: String) =
         statementWhere(patch(tableName), Where.jsonPathMatches())
 }

src/main/kotlin/query/RemoveFields.kt

@@ -0,0 +1,74 @@
+package solutions.bitbadger.documents.query
+
+import solutions.bitbadger.documents.*
+import solutions.bitbadger.documents.query.byFields as byFieldsBase
+import solutions.bitbadger.documents.query.byId as byIdBase
+
+/**
+ * Functions to create queries to remove fields from documents
+ */
+object RemoveFields {
+
+    /**
+     * Create a query to remove fields based on the given parameters
+     *
+     * @param tableName The name of the table in which documents should have fields removed
+     * @param toRemove The parameters for the fields to be removed
+     * @return A query to remove fields from documents in the given table
+     */
+    private fun removeFields(tableName: String, toRemove: List<Parameter<String>>) =
+        when (Configuration.dialect("generate field removal query")) {
+            Dialect.POSTGRESQL -> "UPDATE $tableName SET data = data - ${toRemove[0].name}::text[]"
+            Dialect.SQLITE -> toRemove.joinToString(", ") { it.name }.let {
+                "UPDATE $tableName SET data = json_remove(data, $it)"
+            }
+        }
+
+    /**
+     * A query to patch (partially update) a JSON document by its ID
+     *
+     * @param tableName The name of the table where the document is stored
+     * @param toRemove The parameters for the fields to be removed
+     * @param docId The ID of the document to be updated (optional, used for type checking)
+     * @return A query to patch a JSON document by its ID
+     */
+    fun <TKey> byId(tableName: String, toRemove: List<Parameter<String>>, docId: TKey? = null) =
+        byIdBase(removeFields(tableName, toRemove), docId)
+
+    /**
+     * A query to patch (partially update) a JSON document using field match criteria
+     *
+     * @param tableName The name of the table where the documents are stored
+     * @param toRemove The parameters for the fields to be removed
+     * @param fields The field criteria
+     * @param howMatched How the fields should be matched (optional, defaults to `ALL`)
+     * @return A query to patch JSON documents by field match criteria
+     */
+    fun byFields(
+        tableName: String,
+        toRemove: List<Parameter<String>>,
+        fields: Collection<Field<*>>,
+        howMatched: FieldMatch? = null
+    ) =
+        byFieldsBase(removeFields(tableName, toRemove), fields, howMatched)
+
+    /**
+     * A query to patch (partially update) a JSON document by JSON containment (PostgreSQL only)
+     *
+     * @param tableName The name of the table where the document is stored
+     * @param toRemove The parameters for the fields to be removed
+     * @return A query to patch JSON documents by JSON containment
+     */
+    fun byContains(tableName: String, toRemove: List<Parameter<String>>) =
+        statementWhere(removeFields(tableName, toRemove), Where.jsonContains())
+
+    /**
+     * A query to patch (partially update) a JSON document by JSON path match (PostgreSQL only)
+     *
+     * @param tableName The name of the table where the document is stored
+     * @param toRemove The parameters for the fields to be removed
+     * @return A query to patch JSON documents by JSON path match
+     */
+    fun byJsonPath(tableName: String, toRemove: List<Parameter<String>>) =
+        statementWhere(removeFields(tableName, toRemove), Where.jsonPathMatches())
+}